JP2000200411A - Magnetic recording medium, recording / reproducing head, and magnetic recording / reproducing method - Google Patents

Abstract

[PROBLEMS] To provide a magnetic recording medium which suppresses data loss due to a thermomagnetic relaxation phenomenon, a recording / reproducing head thereof, and a novel magnetic recording / reproducing method using the same. A magnetic recording medium includes a recording auxiliary layer, a recording holding layer, a recording control layer, and a recording layer on a substrate. The recording layer 5 is formed using a ferrimagnetic material having perpendicular magnetization. Since the recording layer 5 has perpendicular magnetization, data can be recorded at a very high density by using the recording / reproducing head of the present invention. The recording layer 5
Has a large coercive force at room temperature, so after data recording,
Data loss due to the thermomagnetic relaxation phenomenon is suppressed. The data recorded at an extremely high density on the magnetic recording medium 100 can be reproduced, for example, using a magnetoresistive element mounted on a recording / reproducing head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium using a magnetic film having perpendicular magnetization for a recording layer, a recording / reproducing head and a magnetic recording / reproducing method. Prevent or suppress the disappearance of
The present invention relates to a magnetic recording medium capable of recording / reproducing at an areal recording density of ²⁰ Gbits / in ² or more, a recording / reproducing head suitable for the recording / reproducing, and a novel magnetic recording / reproducing method using the same.

[0002]

2. Description of the Related Art Hard disks (magnetic recording media) are widely used as external storage media for computers and the like. Hard disks typically employ longitudinal magnetic recording in which information is recorded parallel to the recording film surface using a ring-shaped magnetic head (hereinafter, referred to as a ring head) mounted on a flying slider.

In recent years, the variety of data, such as graphic data, moving image data, and document data, has been diversified, and the amount of information handled has become enormous. Increasing the surface recording density is one of the most important technical issues in the field of hard disks in order to handle such huge data. At this time,
The hard disk achieves an areal recording density of ⁴ Gbits / in ² .

By the way, as one means of high density,
For example, IEEE Transactions on Magnetics, Vol.MAG-15,
No. 6, pp. 1456-1458 (1979) describes a perpendicular magnetic recording method and a perpendicular magnetic recording medium in which information is recorded in a direction perpendicular to the recording film surface using a Co-Cr film having perpendicular magnetization as a recording film. Has been proposed.

[0005]

It is known that the surface recording density of a hard disk can be further increased by reducing the size of magnets (magnetic particles) as recording units constituting a recording layer. However, when the magnetic particles are miniaturized and the areal recording density is 10 to 20 Gbits / in ² or more, there is a problem that the magnetic particles become unstable due to a thermomagnetic relaxation phenomenon, and the recorded data is lost.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to stabilize fine particles even when the surface recording density is increased by miniaturizing magnetic particles as recording units. It is an object of the present invention to provide a magnetic recording medium which can exist and can reproduce minutely recorded information at a high S / N ratio.

Another object of the present invention is to provide a recording and reproducing head suitable for recording and reproducing information using such a magnetic recording medium.

Still another object of the present invention is to provide a novel magnetic recording medium and a recording / reproducing head capable of recording information at an extremely high density and reproducing the recorded information at a high S / N ratio. Another object of the present invention is to provide a simple magnetic recording and reproducing method.

[0009]

According to a first aspect of the present invention, there is provided a magnetic recording medium comprising: a substrate; a recording holding layer made of a magnetic material; and a ferrimagnetic material having perpendicular magnetization. And a recording layer applied thereto, while applying a recording magnetic field while heating a predetermined area of the magnetic recording medium, the recording magnetic domain of the recording layer is reversed to record information, and the magnetic field from the recording magnetic domain of the recording layer is removed. There is provided a magnetic recording medium characterized in that information is reproduced by detection.

[0010] The magnetic recording medium of the present invention comprises a recording layer formed of a ferrimagnetic material having perpendicular magnetization, and a recording holding layer formed of a magnetic material. The record holding layer can be made of, for example, a ferrimagnetic material or an antiferromagnetic material, and is preferably provided between the substrate and the recording layer. In particular, it is preferable that the recording holding layer is provided so as to be in contact with the recording layer. With this arrangement, the recording holding layer can be exchange-coupled with the recording magnetic domains of the recording layer, and can maintain the recording magnetic domains in a stable state in the vertical direction. Ferrimagnetic materials that can be used for the recording holding layer include, for example, T
bFeCo, GdTbFeCo, TbFeCoCr, T
bFe, GdFeCo, GdTbFe or DyTbF
Rare earth-transition metal alloys such as e are preferred. Further, as an antiferromagnetic material that can be used for the recording holding layer, a transition metal (C
r, Mn, Fe, Co, Ni) alloys and precious metals (Au, P)
t, Rh, Pd) and transition metals (Cr, Mn, Fe, C)
o, Ni), transition metal oxides and the like are preferable,
For example, FeMn, NiO, NiMn, PtMn, Fe
NiMn, AuMn, ZnZr, FeRh and the like are preferable.

In the magnetic recording medium of the present invention, in order to secure the thermal stability of the recording magnetic domain of the recording layer, the storage temperature of the medium is from room temperature (about 10 ° C.) to the temperature in the apparatus (about 100 ° C.).
It is necessary that the recording layer has a coercive force of 5 kOe or more in the temperature range of about. Therefore, the recording layer preferably has a coercive force of 5 kOe or more in a temperature range of 10 ° C to 150 ° C. However, this is not the case when a reproducing layer for increasing the magnetic field from the recording layer is used as described later. Further, when reproducing information recorded on the recording layer, a magnetic field generated from a recording magnetic domain of the recording layer is detected. Therefore, it is more advantageous to use a recording layer having a high Curie temperature. Therefore, in order to obtain a sufficient magnetic field strength from the recording magnetic domain near the reproducing temperature at the time of reproducing, the recording layer has a thickness of 30 μm.
It preferably has a Curie temperature of 0 ° C. or higher.

As described above, by using the recording layer having a large coercive force in the temperature range of 10 ° C. to 150 ° C.,
Even if minute recording marks are formed on the recording layer, the disappearance of the recording marks due to the thermomagnetic relaxation phenomenon after recording is suppressed. Further, at the time of recording, the coercive force of the recording layer can be reduced by heating the magnetic recording medium to 200 ° C. or higher, so that recording can be easily performed with a weak applied magnetic field. To reproduce the recorded information, the magnetic field from the recording magnetic domain of the recording layer is directly detected by, for example, a magnetoresistive element to reproduce the information. That is, the magnetic recording medium of the present invention is different from a magneto-optical recording medium that detects a magnetization state using a magneto-optical effect (for example, the Kerr effect).

[0013] The magnetic recording medium of the present invention may further include a reproducing layer on the recording layer. The reproduction layer is at room temperature or higher, preferably at a temperature range of 20 ° C. to 150 ° C.
It is preferable to have a saturation magnetization higher than the saturation magnetization of the recording layer. That is, since the reproducing layer can generate a larger leakage magnetic field than the recording layer, an amplified reproduction signal can be obtained by transferring the magnetization of the recording layer to the reproducing layer and detecting the magnetization state of the reproducing layer. Can be. The reproducing layer may be an in-plane magnetic film or a perpendicular magnetic film.

The magnetic recording medium of the present invention may further comprise a recording auxiliary layer exhibiting soft magnetism. As a material constituting such a recording auxiliary layer, for example, permalloy (Ni
Fe), Fe- (Al, Si) alloy, NiFe- (M
o, Cr, Cu, Mn, Rh) and Co-based amorphous alloys. Further, it is desirable that the recording auxiliary layer is formed so that a magnetic field is applied through the recording layer. That is, when a magnetic field is applied from the substrate side, the substrate, the recording layer, and the recording auxiliary layer can be provided in this order. The structure can be such that the auxiliary layer and the recording layer are provided in this order. If the recording layer and the recording auxiliary layer are laminated in the above order, an arbitrary layer may be interposed between the layers.

Further, in the present invention, an arbitrary layer can be provided in addition to the recording auxiliary layer and the recording holding layer. For example, if the recording layer and the recording holding layer are exchange-coupled to each other at the time of recording, it becomes difficult to perform recording corresponding to the recording data. Therefore, the temperature when a predetermined area of the medium is heated at the time of recording (hereinafter, the recording temperature) It is preferable to provide a recording control layer for cutting the exchange coupling between the two layers at the vicinity of the Curie temperature of the recording layer in the embodiments described later. In order to break the exchange coupling at the recording temperature, the Curie temperature of the recording control layer may be set to be equal to or lower than the Curie temperature of the recording layer. Further, it is also possible to form, for example, a fomblin-based or silicon-based lubrication layer on the surface of the magnetic recording medium. By providing the lubricating layer, even when the recording / reproducing head comes into contact with the magnetic recording medium during recording / reproducing, the recording / reproducing head can be slid smoothly on the surface of the medium. Can be reduced.

In the magnetic recording medium of the present invention, a texture can be provided on the surface of the substrate. By providing a texture on the surface of the substrate, the flying height of the flying head when the flying head is floated on the medium can be controlled to be constant.

According to a second aspect of the present invention, in a recording method for recording information on a magnetic recording medium having a recording layer on a substrate, a magnetic head is used while applying heat to a predetermined area of the magnetic recording medium. The information is recorded by applying a magnetic field having at least one of intensity and direction modulated according to the information to be recorded, and the recording layer is formed using a ferrimagnetic material having perpendicular magnetization. A recording method for a magnetic recording medium is provided, wherein a width of a magnetic pole in a direction perpendicular to a recording direction of the head is 1 μm or less.

In the recording method of the present invention, for example, a laser beam can be used to heat a predetermined region of the magnetic recording medium, and the laser beam is focused on the predetermined region of the medium with an objective lens and irradiated. Can be heated. This makes it possible to reduce the coercive force of the recording layer only in a predetermined high-temperature region where the laser light is focused, and to reverse the magnetization only in that range to form a minute recording magnetic domain. To guide the laser light to the objective lens,
Preferably, an optical fiber is used. The optical fiber can efficiently guide the laser light from the laser light source to the objective lens in terms of energy. Further, as another method of heating a predetermined area of the magnetic recording medium, a heater such as a coil heater can be used, and an area at a position of 1 μm or less from the surface of the magnetic recording medium is heated by radiant heat from the heater. Can be.

In the recording method of the present invention, for example, a series of information can be divided and recorded simultaneously at a plurality of positions on a magnetic recording medium by using a plurality of recording magnetic heads. This makes it possible to improve the information transfer speed.

According to a third aspect of the present invention, in a reproducing method for reproducing information recorded on a magnetic recording medium having a recording layer, the recording layer is made of a ferrimagnetic material having perpendicular magnetization. A method for reproducing information recorded on a recording layer using a kind of magnetic element selected from the group consisting of a resistive element, a magnetic element having a spin-valve film, and an inductive magnetic element. Is provided.

In the reproducing method of the present invention, the recorded information is
Reproduction is performed using, for example, a magnetoresistive element, a magnetic element having a spin valve film, or an inductive magnetic element (inductive magnetic head) while applying heat to a predetermined area of the magnetic recording medium. The magnetic recording medium may be heated during information reproduction. For example, the magnetic recording medium can be heated by irradiating a laser beam or applying radiant heat from a heater or the like. At the time of recording, recording can be performed by applying heat to a predetermined area of the magnetic recording medium and applying a magnetic field in which at least one of intensity and direction is modulated according to recording information. Further, a series of information recorded at a plurality of positions on the magnetic recording medium can be simultaneously reproduced, for example, by using a plurality of magnetic heads equipped with any of the above-described magnetic elements.

According to a fourth aspect of the present invention, in a method for recording information on an information recording medium having a recording layer having perpendicular magnetization on a substrate, the information recording medium is irradiated with a light spot while irradiating the information recording medium with a light spot. There is provided a recording method for an information recording medium, wherein information is recorded by applying a magnetic field only to an area located inside a spot and smaller than a light spot.

In the recording method of the present invention, while irradiating the information recording medium with a light spot, a magnetic field is applied using, for example, a single-pole head capable of perpendicular magnetic recording.
A recording mark smaller than the light spot is formed in an area inside the light spot. This enables ultra-high density recording. In order to form a recording mark smaller than the light spot, for example, an FIB (focus beam) is used so that the tip of the single pole head where the magnetic field lines are generated is smaller than the light spot diameter.
d ion beam).

According to a fifth aspect of the present invention, in a recording and / or reproducing head for a magnetic recording medium, a magnetic field source for applying a recording magnetic field to the magnetic recording medium; A magnetic element selected from the group consisting of a magnetoresistive element, a magnetic element having a spin valve film, and an inductive magnetic element; and air on which the magnetic field source and the magnetic element are mounted. And a slider for recording and / or reproducing.

The head of the present invention can further include a heat source for heating the magnetic recording medium. As the heat source, for example, a laser light source can be used, and a predetermined region of the medium can be heated by converging and irradiating laser light emitted from the laser light source onto the medium with an objective lens or the like. To guide the laser light to the objective lens, for example, an optical fiber can be used. Further, it is desirable that the heat source is provided so as to be disposed ahead of the magnetic element in a direction in which the heat source moves relatively to the magnetic recording medium. In this specification, in a direction (medium moving direction) in which a recording area of a recording medium moves with respect to an object (for example, a heat source or a head), the object is first placed on the recording medium when the object is used as a reference. The side that reaches the recording area of the recording medium is referred to as “front side in the medium moving direction”, and the side that reaches the recording area of the recording medium later is referred to as “rear side in the medium moving direction”.

In the head of the present invention, the magnetic field generating source for applying the recording magnetic field to the magnetic recording medium can be constituted by using, for example, a single pole head 220 as shown in FIG. The single magnetic pole head 220 includes a core (main magnetic pole) 225, a main body 221, and a connecting portion 223 thereof.
And a coil 224 wound around the periphery. A protective film may be formed on the inner wall of the core 225. When the core 225 is opposed to a magnetic recording medium having a plurality of tracks, for example, the width of the leading end of the core in the track width direction of the magnetic recording medium is 1 μm or less.
It is preferably processed by IB (focused ion beam). As a result, information can be recorded on the magnetic recording medium at a very high density. Further, the magnetic field generating part or the whole of the single pole head is made of, for example, CoNiFe or CoNiF.
By using a material having a saturation magnetic flux density (Bs) of 2.0 T or more such as an e-alloy system, the magnetic force generated from the single-pole head can be increased, and recording on a recording medium having a high coercive force can be performed. Becomes possible.

In the head of the present invention, the magnetoresistive element is an element (MR) whose electric resistance changes according to a change in the magnetic field.
Element: Magneto-Resistive Device), which can detect the perpendicular magnetization state of the recording layer and the perpendicular or in-plane magnetization state of other magnetic layers. As a material of the MR element, for example, FeMn / CoNi / Cu / C
o. Further, a magnetic element including a spin valve film or a magnetic element such as an induction type magnetic head can be used. The spin valve film is made of, for example, CoFe / Cu / CoFe /
It can be formed from Ru / CoFe / MnPt. Also, MR
It is also possible to use a GMR (Giant Magneto-Resistive) element having a larger rate of change in electric resistance with respect to a magnetic field change than the element, instead of the magnetoresistive element.

In the present invention, it is desirable that the air slider is formed using a plurality of materials having different thermal conductivity. In particular, it is desirable to use a material having the lowest thermal conductivity among a plurality of materials having different thermal conductivity between the magnetic field generating source and the magnetoresistive element. This prevents the magnetoresistive element from being heated by the heat generated by the magnetic field generation source. In addition, by forming the material having the highest thermal conductivity among a plurality of materials having different thermal conductivity on a portion that comes into contact with the outside air, for example, on the upper surface of the head, heat generated by a magnetic field generation source is radiated to the outside of the head. Can be.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetic recording medium, a recording / reproducing head and a magnetic recording / reproducing method of the present invention will be specifically described with reference to the drawings.

Embodiment 1 FIG. 1 is a schematic sectional view of a specific example of a magnetic recording medium according to the present invention. The magnetic recording medium 100 is formed by sequentially laminating a recording auxiliary layer 2, a recording holding layer 3, a recording control layer 4, a recording layer 5, a protective layer 6, and a lubricant layer 7 on a substrate 1.

In FIG. 1, a substrate 1 is made of glass and has a diameter of 90 mm and a thickness of 1.2 mm. The substrate 1 may be provided with a texture for stabilizing the flying height of the head. The recording auxiliary layer 2 on the substrate 1 is a soft magnetic film and is made of NiFe (permalloy) having high magnetic permeability. The Curie temperature Tc6 of NiFe is 50
0 ° C., and the coercive force Hc6 was 0.1 Oe or less in the temperature range from room temperature to the Curie temperature Tc6.

The recording holding layer 3 is made of an antiferromagnetic material FeMn exhibiting perpendicular magnetic anisotropy, and has a Curie temperature Tc3.
Was adjusted to 450 ° C. The recording control layer 4 is made of an amorphous ferrimagnetic material Dy exhibiting perpendicular magnetic anisotropy.
It is composed of FeCo and has a Curie temperature Tc2 of 20.
The composition was adjusted to be 0 ° C. DyFeCo constituting the recording control layer 4 has a Curie temperature T from room temperature.
The polarity of rare earth dominance (RE-rich) is shown toward c2.

The recording layer 5 is made of an amorphous ferrimagnetic material TbFeCo exhibiting perpendicular magnetic anisotropy. As shown in the magnetic characteristic graph of FIG.
5 kOe or more in the temperature range from room temperature to 100 ° C., 200
The composition was adjusted such that the temperature became 2 kOe or less in a temperature range of from 0 ° C. to 300 ° C., the Curie temperature Tc was 300 ° C., and the compensation temperature was near room temperature. The protective layer 6 is formed using a non-magnetic material SiN.

These layers 2 to 6 were sequentially formed by sputtering using a sputtering apparatus. The film thickness of each layer was 500 nm for the recording auxiliary layer, 30 nm for the recording holding layer, 10 nm for the recording control layer, 100 nm for the recording layer 5, and 10 nm for the protective layer 6.

Next, a lubricant layer 7 having a thickness of 2 nm was applied to the surface of the protective film 6 by spin coating. For the lubricant layer 7, a heptane solution containing dimethyl silicone to which modified silicone and fatty acid were added as main components was used. Thus, the magnetic recording medium 100 having the structure shown in FIG. 1 was manufactured.

FIG. 2 shows a specific example of a recording / reproducing head according to the present invention. The recording / reproducing head 200 includes a head main body 20 and a heat source 31 for heating a magnetic recording medium. The head body 20 includes an air slider 21.
And a recording magnetic head 22 and a reproducing MR head 23 mounted on the air slider 21. The air slider 21 is formed using a ceramic material.
By using the air slider 21, the head body 2
0 can be levitated at a predetermined interval from the medium surface. In the present embodiment, the head body 20 is designed so as to float at a height of 50 nm from the surface of the magnetic recording medium 100 during recording and reproduction.

The recording magnetic head 22 is used for the magnetic recording medium 1.
The head is a single pole head capable of applying a magnetic field in a direction perpendicular to the surface of the magnetic pole 00, and includes a magnetic coil 24 and an iron core 25. The iron core 25 is made of N having a large high-frequency magnetic permeability.
It is made of iFe and has a columnar shape extending in the vertical direction of the head main body 20 (the vertical direction in FIG. 2). The tip of the iron core 25 on the side facing the magnetic recording medium 100 is in a direction perpendicular to the track direction (track width direction).
FIB (focused beacon) so that the width of
m). The magnetic coil 24 is made of a copper wire and is provided so as to go around the outer periphery of the iron core 25. By using the recording magnetic head 22 having such a structure to generate a magnetic field modulated in accordance with recording data, a minute recording mark can be formed on the magnetic recording medium 100. The recording magnetic head 22 can generate a maximum magnetic field of 500 Oe. Also, by forming the tip of the single pole head using, for example, CoNiFe or an alloy containing it and having a saturation magnetic flux density (Bs) of 2.0 T or more, a magnetic field of 1000 Oe or more can be generated. It becomes possible.

The reproducing MR head 23 is a perpendicular magnetization reproducing MR head capable of detecting the magnetization state in the vertical direction. The MR element is composed of FeMn / CoNi / C.
u / Co. The reproducing MR head 23 is provided rearward (leftward in FIG. 2) of the recording magnetic head 22 in the traveling direction of the magnetic recording medium 100 indicated by an arrow in FIG. Data perpendicularly recorded in the layer can be read. Further, instead of the MR element, CoFe / Cu / CoFe / Ru / CoFe /
By using a magnetic element having a spin valve film such as MnPt, the magnetic field sensitivity can be further improved.

In the head main body 20, heat radiating members 26a and 26b are provided between the reproducing MR head 23 and the recording magnetic head 22 and on the upper surface of the head main body, respectively. The heat radiating members 26a and 26b are both made of Al having high thermal conductivity. These heat dissipating materials 26a and 26b dissipate the heat generated by the magnetic coil 24 to the outside of the head main body, and can prevent the reproducing MR head 23 from being heated.

The heat source 31 mainly includes a laser light source 27, an objective lens 28, and an optical fiber 29, and is provided at a position facing the head main body 20 with a magnetic recording medium interposed therebetween. The laser light source 27 has an oscillation wavelength of 640.
nm semiconductor laser. NA of objective lens 28
(Numerical Aperture) is 0.6. The laser light emitted from the laser light source 27 is guided to the objective lens 28 by the optical fiber 29, enters the magnetic recording medium from the substrate side, and is focused on a predetermined area of the recording layer.

Recording / Reproducing Experiment A recording / reproducing experiment was performed using the magnetic recording medium 100 and the recording / reproducing head 200. FIG. 4A shows a conceptual diagram of the arrangement of a magnetic recording medium and a recording / reproducing head in a recording / reproducing experiment, and FIG. 4B shows a cross-sectional view thereof. In the recording / reproducing experiment, as shown in FIG. 4A, the magnetic recording medium 100 is installed with a spindle 102 inserted into a central opening (not shown). The recording / reproducing head 200 is disposed on the lubricant layer side (the side opposite to the substrate) of the magnetic recording medium 100. Although not shown, an objective lens for condensing the laser light on the magnetic recording medium 100 is disposed at a position facing the recording / reproducing head 200 with the magnetic recording medium 100 interposed therebetween. The light is condensed and incident from the substrate side of the magnetic recording medium.

Here, the principle of recording data on the magnetic recording medium 100 will be described. First, while rotating the magnetic recording medium 100 at a predetermined linear velocity, a predetermined area of the magnetic recording medium 100 is irradiated with a laser beam focused from the substrate side. FIG. 5A shows the magnetic recording medium 10.
FIG. 0 shows a state where the laser light is focused and irradiated from the substrate side (the lower side in the figure). In FIG. 5A, it is assumed that the magnetic recording medium 100 moves to the left. As shown in the graph of the temperature distribution in FIG.
Maximum temperature Tmax of the area irradiated by light spot 41
(The maximum value of the temperature showing the Gaussian distribution) is equal to or lower than the Curie temperature Tc3 (450 ° C.) of the recording holding layer 3 and, of the regions irradiated with the light spot 41, the region to which the external magnetic field is applied (hereinafter, the magnetic field The temperature of the region including the application region 42 is adjusted so as to be equal to or higher than the Curie temperature Tc (300 ° C.) of the recording layer 5. Simultaneously with the irradiation of the laser beam, an external magnetic field Hex is applied vertically upward to the surface of the magnetic recording medium using the recording magnetic head 22 (single pole head). At this time, the magnetic field application area 42 of the recording layer is smaller than the light spot 41.

In FIG. 5A, the magnetic recording medium 100
Move to the left with respect to the light spot, the magnetic field application region 42 is cooled off the light spot. FIG. 5 (b)
FIG. 7 shows how the magnetization of each magnetic layer changes in the process of cooling the magnetic field application region 42. In the cooling process, when the temperature T of the magnetic field application region 42 becomes Tc2 (Curie temperature of the recording control layer: 200 ° C.) <T <Tc (300 ° C.), the magnetization of the magnetic field application region of the recording layer becomes the direction of the external magnetic field Hex. (Upward in the figure) and appear in TM-rich (transition metal dominant). Then, when room temperature <T <Tc2 (200 ° C.), the magnetization of the recording control layer appears in the same direction as the magnetization of the recording layer by exchange coupling, and at the same time, the magnetization state of the recording layer by exchange coupling with the magnetization of the recording holding layer. Is firmly fixed in the vertical direction. In addition, the magnetic flux (external magnetic field) generated from the tip of the core of the recording magnetic head 22 (single pole head) passes through the recording layer while being converged by the recording auxiliary layer showing soft magnetism. In this way, information is recorded on the recording layer at a very high density.

The above is the recording principle of the magnetic recording medium 100 having the laminated structure shown in FIG. Magnetic recording medium 100
The data was recorded under the following conditions. Magnetic recording medium 100
While rotating at a linear velocity of 1.0 m / s, an external magnetic field is modulated and applied at 6.25 MHz at a magnetic field strength of 300 Oe using a recording / reproducing head 200, and at the same time, a laser with a laser power of 8 mW is applied. Light was irradiated from the substrate side. Thus, the track pitch (TP) 0.
Recording was performed at 4 μm and a bit pitch (BP) of 0.08 μm. This corresponds to an areal recording density of 20.1 Gbits / in ² ,
This corresponds to a data transfer rate of 12.5 Mbits / s.

With respect to the magnetic recording medium 100 on which recording was performed as described above, the magnetization state (recording data) of the recording layer was detected using the recording / reproducing head 200, and the S / N ratio was measured. Next, in order to examine the environmental durability of the magnetic recording medium, the magnetic recording medium is left for a predetermined time under the environment of the following three conditions while holding the recording data, and then S
The / N ratio was measured. Here, environment 60 ° C, 90% R
H, environment 70 ° C, 90% RH, environment 80 ° C, 90%
RH. FIG. 6 is a graph showing how the S / N ratio of the magnetic recording medium changes under each environment. In the graph of FIG. 6, the vertical axis represents the S / N ratio (relative S / N ratio) as a relative value obtained by standardizing the S / N ratio measured after standing in the above environment with the S / N ratio measured before standing. Ratio). From the graph of FIG. 6, it can be seen that even in the harshest environments, 10
It can be seen that the relative S / N ratio of 95% or more is maintained even after 000 hours.

Next, Co, which exhibits perpendicular magnetization, is used as the recording layer.
The durability of the S / N ratio under the environment of 80 ° C. and 90% RH was examined for the conventional magnetic recording medium using the Cr-based magnetic material and the magnetic recording medium of the present invention. First, TP = 1.6 using a conventional ring head on a conventional magnetic recording medium.
Magnetic recording was performed (longitudinal recording) at .mu.m and BP = 0.2 .mu.m ( ² Gbits / in.sup.2), and information recorded using an MR head was reproduced to measure the S / N ratio. Next, the sample was left for a predetermined time in the above environment (80 ° C., 90% RH), and then the S / N ratio was measured again using the MR head. Next, TP = 1.6 μm and BP = 0.2 using the recording / reproducing head 200 of the present invention on the magnetic recording medium 100 of the present invention.
Recording was performed at μm ( ² Gbits / in ² ), and the recorded information was reproduced using the recording / reproducing head 200 of the present invention, and the S / N ratio was measured. Then, the above environment (80 ° C 9
(0% RH) for a predetermined time, and then the S / N ratio was measured again using the recording / reproducing head 200 of the present invention. The graph of FIG. 7 shows how the S / N ratio of the conventional magnetic recording medium and the magnetic recording medium of the present invention changes. In the graph of FIG. 7, the vertical axis represents the S / N ratio (relative S / N ratio) as a relative value obtained by standardizing the S / N ratio measured after standing in the above environment with the S / N ratio measured before standing. / N ratio). As can be seen from the graph of FIG. 7, in the conventional magnetic recording medium, under an environment of 80 ° C. and 90% RH, the relative S / N ratio significantly decreases, and after one hour, the relative S / N ratio is 0.4 or less. Had fallen to. On the other hand, the magnetic recording medium of the present invention
The high relative S / N ratio is maintained even after 5 hours. This indicates that the magnetic recording medium of the present invention has higher environmental durability than the conventional magnetic recording medium.

Next, the dependence of the reproduction output on the recording mark length was examined for the magnetic recording medium 100 according to the present invention and the conventional magnetic recording medium. Regarding the recording mark dependency, with respect to the magnetic recording medium 100 of the present invention, recording is performed with various recording mark lengths using the head according to the present invention, and reproduced using a giant magnetoresistive (GMR) head. Was performed. On the other hand, for a conventional magnetic recording medium, recording was performed using a conventional ring head (longitudinal recording), and reproduction was performed using a GMR head. In both the magnetic recording medium of the present invention and the conventional magnetic recording medium, the track pitch was 1.6 μm, and the GMR head used had a shield interval of 0.2 μm. FIG. 8 is a graph showing how the reproduction output changes with the recording mark length of the magnetic recording medium of the present invention and the conventional magnetic recording medium. In the graph of FIG. 8, the vertical axis indicates a reproduction output normalized by a reproduction signal amplitude when a recording mark having a recording mark length of 1.0 μm is reproduced in a conventional magnetic recording medium.
As can be seen from the graph of FIG. 8, the magnetic recording medium of the present invention has a higher reproduction output than the conventional magnetic recording medium when the recording mark length is reduced to 0.2 μm or less.

Embodiment 2 FIG. 9 is a schematic cross-sectional view of a specific example of a magnetic recording medium according to the present invention, which is different from Embodiment 1. The magnetic recording medium 300 is a magnetic recording medium in which the reproducing layer 8 is provided between the recording layer 5 and the protective layer 6 of the magnetic recording medium 100 shown in FIG. The layer 3, the recording control layer 4, the recording layer 5, the reproducing layer 8, the protective layer 6, and the lubricant layer 7 are sequentially laminated. In the magnetic recording medium 300 having such a structure, the material of the recording control layer 4 is changed to amorphous ferrimagnetic TbFeCo, the thickness of the recording layer 5 is changed to 50 nm,
It was manufactured in the same manner as in Example 1 except that the reproducing layer 8 was formed to have a thickness of 20 nm.

In FIG. 9, the recording control layer 4 is composed of an amorphous ferrimagnetic film TbFeCo exhibiting perpendicular magnetic anisotropy, and its composition is adjusted so that its Curie temperature Tc2 becomes 200 ° C. The recording control layer 4 has a rare-earth dominant (RE-rich) polarity from room temperature to the Curie temperature Tc2.

The reproducing layer 8 is made of an amorphous ferrimagnetic film GdFe
Co, whose Curie temperature Tc4 is 350
At C the compensation temperature Tcomp4 is below room temperature. The transition metal dominant (TM-rich) perpendicular magnetic anisotropy is exhibited from room temperature to the Curie temperature, and the coercive force Hc4 is 500 Oe or less. The saturation magnetization Ms of the reproducing layer 8 is larger than the saturation magnetization Ms of the recording layer 5 at room temperature or higher as shown in FIG.

Recording / Reproduction Experiment A recording / reproduction experiment was performed in the same manner as in Example 1 except that the magnetic recording medium 100 in the recording / reproduction experiment described in Example 1 was changed to the magnetic recording medium 300 manufactured in this example. .

Here, the recording principle of the magnetic recording medium 300 will be described. First, while rotating the magnetic recording medium 300 at a predetermined linear velocity, a predetermined area of the magnetic recording medium 300 is irradiated with a laser beam focused from the substrate side. FIG. 11A shows a state in which the magnetic recording medium 300 is irradiated with laser light condensed from the substrate side (the lower side in the figure). In FIG. 11A, it is assumed that the magnetic recording medium 300 moves to the left. As shown in the temperature distribution graph of FIG. 11A, the laser power is such that the maximum temperature Tmax (the maximum value of the temperature showing the Gaussian distribution) of the area irradiated with the light spot 41 is the Curie of the recording holding layer 3. Temperature Tc3
(450 ° C.) or lower, and the temperature of the region including the magnetic field application region 42 among the regions irradiated with the light spot 41 was adjusted to be equal to or higher than the Curie temperature Tc4 (350 ° C.) of the reproducing layer 8. Simultaneously with the irradiation of the laser beam, the magnetic recording medium 300 is used by using the recording magnetic head 22 (single-pole head).
An external magnetic field Hex is applied vertically upward to the surface of the substrate. At this time, the magnetic field application area 42 is smaller than the light spot 41.

In FIG. 11A, the magnetic recording medium 30
Since 0 moves to the left with respect to the light spot, the magnetic field application region 42 is cooled off the light spot. FIG.
(B) shows how the magnetization of each magnetic layer changes in the process of cooling the magnetic field application region 42. In the process of cooling the magnetic field application region 42, the temperature T of the magnetic field application region 42 becomes Tc
(300 ° C.) <T <Tc4 (350 ° C.), the magnetization of the magnetic field application region of the reproducing layer is oriented in the direction of the external magnetic field Hex (FIG. 1).
1, upward) in TM-rich. Tc2
When (200 ° C.) <T <Tc (300 ° C.), the magnetization of the recording layer located immediately below the magnetic field application region of the reproducing layer changes the direction of the external magnetic field Hex (upward in FIG. 11B) to TM-r.
Appear on ich. When room temperature <T <Tc2 (200 ° C.), the magnetization of the recording control layer located immediately below the recording layer becomes
By exchange coupling with the recording layer, it appears in the same direction as the magnetization of the recording layer, and at the same time, the magnetization state of the recording layer is firmly fixed by exchange coupling with the magnetization of the recording holding layer. According to such a recording principle, information is recorded on the recording layer at an extremely high density. In addition,
In the above recording process, the magnetic flux (external magnetic field) generated from the tip of the core of the recording magnetic head 22 (single pole head) passes through the recording layer while being converged by the recording auxiliary layer exhibiting soft magnetism.

To reproduce information recorded at a very high density, the magnetization state of the reproducing layer is detected by using the reproducing MR head 23 mounted on the recording / reproducing head 200. As described above, at room temperature, the saturation magnetization of the reproducing layer is larger than the saturation magnetization of the recording layer, so that the leakage magnetic field to the reproducing MR head 23 increases. Therefore, the sensitivity is improved and the amplitude of the reproduced waveform is increased as compared with the case where the magnetization state of the recording layer is reproduced using the direct reproducing MR head 23 as in the first embodiment. Further, as shown in the graph of FIG. 10, since the saturation magnetization of the reproducing layer increases as the temperature increases from room temperature, it is necessary to further increase the reproduction waveform amplitude by heating the magnetic recording medium with a low laser power during reproduction. Can be. The above is the principle of reproduction of the magnetic recording medium 300 having the laminated structure shown in FIG.

Next, data was recorded on the magnetic recording medium 300 under the following conditions. When the magnetic recording medium 300 has a linear velocity of 1.0
m / s, the recording magnetic head was modulated at 6.25 MHz with an intensity of 300 Oe, and simultaneously irradiated with 8 mW laser light to obtain a track pitch (TP) of 0.4 μm.
m, and recording was performed at a bit pitch (BP) of 0.08 μm. This corresponds to an areal recording density of 20.1 Gbits / in ² and a data transfer rate of 12.5 Mbits / s.

As described above, TP = 0.4 μm, BP
Using the reproducing MR head 22, the following two reproducing conditions were used for the magnetic recording medium 300 on which recording was performed at 0.08 μm = (0.08 μm), and (b) a laser with a laser power of 1.4 mW. When light was applied, information was reproduced and the S / N ratio was measured. As a result, the result that the S / N ratio was larger in the case of the reproduction condition (b) than in the case of the reproduction condition (a) was obtained.

Embodiment 3 FIG. 12 is a schematic sectional view showing another specific example of the magnetic recording medium according to the present invention. The magnetic recording medium 400 is provided on the substrate 1
The recording holding layer 3, the recording control layer 4, the recording layer 5, the reproducing layer 50,
The protective layer 6 and the lubricant layer 7 are sequentially laminated. In the magnetic recording medium 400 having such a structure, in the first embodiment, the recording auxiliary layer 2 is not formed on the substrate 1, but a reproducing layer 50 having characteristics described later is formed on the recording layer 5 to a thickness of 20 nm. The recording control layer 4 was formed using amorphous ferrimagnetic TbFeCo having magnetic properties described later, and was manufactured in the same manner as in Example 1 except that the thickness of the recording holding layer 3 was changed to 50 nm.

In FIG. 12, the recording control layer 4 is formed using an amorphous ferrimagnetic film TbFeCo exhibiting perpendicular magnetic anisotropy, and its composition is adjusted so that the Curie temperature Tc2 becomes 200 ° C. The recording control layer 4 has a rare-earth dominant (RE-rich) polarity from room temperature to the Curie temperature. The reproducing layer 50 is composed of an amorphous ferrimagnetic film GdFeCo having a Curie temperature Tc4 of 280 ° C., and exhibits an in-plane magnetization from room temperature to 150 ° C., and has a composition so as to exhibit perpendicular magnetization at 150 ° C. or higher. It was adjusted. The critical temperature at which the stable magnetization direction changes from in-plane to perpendicular is called the perpendicularization temperature and is represented by Tcr4.

FIG. 13 is a schematic diagram showing another specific example of the recording / reproducing head according to the present invention, which is different from the first embodiment. The recording / reproducing head 210 includes a head main body 120 and a laser light source 127 for heating the medium. The laser light source 127 is a semiconductor laser having an oscillation wavelength of 640 nm. The head main body 120 includes an air slider 121,
It comprises a recording magnetic head (magnetic coil) 122 and a reproducing MR head 123 mounted on the air slider 121. The air slider 121 is formed using a ceramic material (or transparent glass). By using the air slider 121, the head body 120
At a predetermined interval from the medium surface.
In this embodiment, the head main body 120 is designed to fly at a height of 50 nm from the surface of the medium during recording and reproduction.

In FIG. 13, the recording magnetic head 122 is used.
Is a single-pole head capable of applying a magnetic field in a direction perpendicular to the medium surface, and includes a magnetic coil 108 and an annular core 105. The core 105 is made of a ferromagnetic material NiFe having a high high-frequency magnetic permeability. As shown in FIG. 13, the outer periphery of the core 105 is fitted so as to be joined to the inner periphery of a through hole 130 formed from the upper surface to the lower surface of the slider. The magnetic coil 108 is made of a copper wire, and is provided below the core 105 so as to go around the outer periphery of the core 105. By using the recording magnetic head 122 to generate an external magnetic field modulated according to recording data, data can be recorded on a medium. The recording magnetic head 122 can generate a magnetic field of 500 Oe at the maximum.

In FIG. 13, the annular core 105
An objective lens 109 for condensing the laser light on the medium is inserted in the inside. NA of objective lens 109
(Numerical Aperture) is 0.85. The objective lens 109 condenses the laser light incident from the upper opening 105a of the core 105 and irradiates the laser light from the lower opening 105b of the core 105 toward the medium.

The reproducing MR head 123 is a perpendicular magnetization reproducing MR head capable of detecting the magnetization state in the vertical direction. The MR element is composed of FeMn / CoNi / C.
u / Co. The reproducing MR head is provided rearward (leftward in FIG. 13) of the recording magnetic head in a direction relatively moving with respect to the magnetic recording medium.
Data that has been perpendicularly magnetically recorded on the recording layer of the magnetic recording medium can be read.

In the head main body 120, the reproducing MR
A heat blocking layer 126a is formed between the head 123 and the recording magnetic head 122. The heat blocking layer 126a is made of ceramic having a low thermal conductivity, and reduces the influence of the heat generated by the magnetic coil 108 on the reproducing MR head 123. Further, a heat radiating material 126b made of Al having high thermal conductivity is formed on the upper surface of the head main body, and the heat generated from the magnetic coil 108 can be radiated to the outside of the head.

Recording and Reproduction of Information Recording and reproduction can be performed using the magnetic recording medium 400 and the recording / reproducing head 210. For recording and reproduction, the magnetic recording medium 400 is loaded into an evaluation device (drive), and the recording / reproducing head 210 is moved to the magnetic recording medium 400.
Is disposed on the lubricant layer side (the side opposite to the substrate).

Here, the principle of recording and reproduction on the magnetic recording medium 400 will be described with reference to FIGS. FIG. 14A shows a state where a predetermined area of the magnetic recording medium 400 is irradiated with laser light condensed from the lubricant layer side (upper side in the figure). The magnetic recording medium 400 is rotating at a predetermined linear speed, and the magnetic recording medium moves leftward in FIG. As shown in the graph of the temperature distribution in FIG.
Maximum temperature Tmax of the area irradiated by light spot 41
(The maximum value of the temperature showing the Gaussian distribution) is equal to or lower than the Curie temperature Tc3 (450 ° C.) of the recording holding layer 3 and the temperature of a part of the area irradiated with the light spot 41 is the Curie temperature Tc4 ( (280 ° C.) or higher. At the same time as irradiating the magnetic recording medium 400 with laser light, an external magnetic field Hex is applied vertically upward to the surface of the magnetic recording medium 400 using the recording magnetic head 122 (single pole head).

In FIG. 14A, the magnetic recording medium 40
When 0 moves to the left side with respect to the light spot, a region heated by irradiation of the light spot (hereinafter, referred to as a high-temperature region)
Is cooled off the light spot. In FIG. 14 (b),
The state where the magnetization of each magnetic layer changes in the cooling process of the high temperature region is shown. When the temperature in the high temperature region is represented by T, FIG.
As shown in (b), Tc4 (Curie temperature of reproducing layer: 280 ° C.) <T <Tc (Curie temperature of recording layer: 3)
00 ° C.), the magnetization in the high temperature region of the recording layer becomes
It appears on TM-rich in the direction of ex (upward).
When Tc2 (200 ° C.) <T <Tc4 (280 ° C.), the magnetization of the reproducing layer located immediately above the recording layer is lowered by RE-rich due to exchange coupling with the magnetization of the recording layer (the sub-lattice magnetization of the transition metal becomes lower). (Upward). Tcr4 (1
When 50 ° C.) <T <Tc2 (200 ° C.), the magnetization of the recording control layer is exchange-coupled with the magnetization of the high-temperature region of the recording layer and appears in the same direction as the magnetization of the recording region of the recording layer, and at the same time, the recording is held. The magnetization state of the recording layer is firmly fixed by exchange coupling with the magnetization of the layer. Room temperature <T <Tcr4 (1
At 50 ° C.), the magnetization of the reproducing layer is directed from the perpendicular direction to the in-plane direction. Thus, information is recorded on the recording layer. The above is the principle of recording.

Next, the principle of reproduction will be described. In order to reproduce information recorded according to the above-described recording principle, the magnetic recording medium 400 is heated by irradiating a reproduction laser beam having a low laser power while rotating the magnetic recording medium 400 at a predetermined linear velocity. FIG. 15 shows a state where a predetermined area of the magnetic recording medium 400 is irradiated with the reproduction laser beam 150. By irradiating the magnetic recording medium 400 with the reproducing laser beam 150, the surface of the magnetic recording medium 400
5 is heated with a temperature distribution as shown in the graph below. In the region above the perpendicular temperature Tcr4 of the reproducing layer, the magnetization changes from the in-plane direction to the perpendicular direction. At this time, the magnetization state of the recording layer located immediately below the reproducing layer is transferred to the reproducing layer by the exchange coupling force. As shown in FIG. 15, the reproducing MR head 123 is located immediately above the boundary where the magnetization of the reproducing layer changes from in-plane magnetization to perpendicular magnetization. Also, MR for reproduction
Since the size of the head 123 is larger than the size of the magnetic domain of the reproducing layer, the magnetizations 151 and 152 of the reproducing layer exist in a region immediately below the reproducing MR head 123. However, since the magnetization 152 of the reproduction layer located on the left side of the reproduction MR head 123 faces in the in-plane direction, it is not detected by the reproduction MR head 123, and the magnetization 151 in one perpendicular direction, that is, reproduction is performed. Only the magnetization information of the recording layer existing immediately below the magnetization of the layer is independently extracted. Also, the in-plane magnetization 152 of the reproducing layer does not affect the magnetization state of the recording layer located immediately below. Further, the saturation magnetization of the reproducing layer is larger than the saturation magnetization of the recording layer as shown in FIG. 10 and becomes larger as the temperature becomes higher. By heating the recording medium, the reproducing MR head 123 can detect a large leakage magnetic field from the reproducing layer. The above is the principle of reproduction of the magnetic recording medium 400.

Embodiment 4 FIG. 16 is a schematic sectional view showing a specific example of a magnetic recording medium according to the present invention, which is different from the above-mentioned Embodiments 1 to 3. Magnetic recording medium 50
No. 0 is obtained by sequentially laminating a recording holding layer 3, a recording control layer 4, a recording layer 5, a mask layer 52, a magnetic transfer layer 54, a protective layer 6, and a lubricating layer 7 on a substrate 1.

The recording holding layer 3 is made of an antiferromagnetic film NiO exhibiting perpendicular magnetic anisotropy, and has a Curie temperature Tc3.
Was adjusted to 450 ° C. The recording control layer 4 was composed of a magnetic film DyFeCo exhibiting perpendicular magnetic anisotropy, and its composition was adjusted so that the Curie temperature Tc2 became 200 ° C. DyFeCo with adjusted composition
Is rare earth dominant from room temperature to Curie temperature (RE-
rich).

The mask layer 52 is made of an amorphous ferrimagnetic film Gd.
The composition was adjusted so that the Curie temperature Tc4 was 300 ° C., and the composition exhibited in-plane magnetization from room temperature to 150 ° C. and perpendicular magnetization at 150 ° C. or higher. The critical temperature at which the stable magnetization direction changes from in-plane to perpendicular is called the perpendicularization temperature and is represented by Tcr4. The magnetic transfer layer 54 is formed using an amorphous ferrimagnetic film GdFeCo, and has a Curie temperature Tc5 of 300 ° C., exhibits perpendicular magnetization from room temperature to 110 ° C., and 110 ° C. to 150 ° C.
The composition was adjusted so as to show in-plane magnetization up to 150 ° C. and to show perpendicular magnetization from 150 ° C. to 300 ° C. Here, the critical temperature (110 ° C.) at which the stable magnetization direction changes from perpendicular to in-plane
Is called an in-plane temperature and is represented by Tcr′5. In addition, the magnetic material of the magnetic transfer layer 54 has a property that the exchange coupling force in the in-plane direction increases at high temperatures.

The materials for the recording layer 5, the protective layer 6, and the lubricating layer 7 were the same as those of the magnetic recording medium manufactured in Example 1. The recording holding layer 3, the recording control layer 4, the recording layer 5, the mask layer 52, the magnetic transfer layer 54, and the protective layer 6 are sequentially formed by sputtering, respectively.
The thickness of each layer is 50 nm, 10 nm, 100 nm,
They were 5 nm, 15 nm and 10 nm. Next, the lubricating layer 7 is coated with the protective layer 6 to a thickness of 2 nm by spin coating.
Formed on top. Thus, a magnetic recording medium 500 having the structure shown in FIG. 16 was manufactured.

Recording and Reproduction of Information The magnetic recording medium 500 of the third embodiment is different from that of the third embodiment in that an MR head 123 ′ for detecting in-plane magnetization is used instead of the MR head 123 for detecting perpendicular magnetization. Recording and reproduction can be performed using a similar recording and reproduction head. Recording and reproduction are performed by loading the magnetic recording medium 500 into an evaluation device (drive) and arranging the recording / reproducing head 210 on the lubricant layer side of the magnetic recording medium 500 (the side opposite to the substrate).

Here, the principle of recording and reproduction on the magnetic recording medium 500 will be described with reference to FIGS. FIG. 17A shows a state in which a predetermined area of the magnetic recording medium 500 is irradiated with laser light focused from the side opposite to the substrate 1 (upper side in the figure). The magnetic recording medium 500 is rotating at a predetermined linear speed, and the magnetic recording medium moves in the left direction in FIG. As shown in the graph of the temperature distribution in FIG.
Maximum temperature Tmax of the area irradiated by light spot 41
(The maximum value of the temperature showing the Gaussian distribution) is equal to or lower than the Curie temperature Tc3 (450 ° C.) of the recording holding layer 3, and the temperature of a part of the region irradiated with the light spot 41 is the Curie temperature Tc ( (300 ° C.) or higher. At the same time as irradiating the magnetic recording medium 500 with laser light, an external magnetic field Hex is applied vertically upward to the surface of the magnetic recording medium 500 using the recording magnetic head 122 (single pole head).

In FIG. 17A, the magnetic recording medium 50
When 0 moves to the left with respect to the light spot 41, a region 45 heated by irradiation of the light spot 41 (high-temperature region)
Is cooled off the light spot 41. FIG. 17 (b)
FIG. 7 shows how the magnetization of each magnetic layer changes during the cooling process of the high-temperature region 45. In FIG. 17B, when the temperature of the high temperature region 45 is represented by T, when Tc4 <T <Tc, the magnetization of the recording layer appears on the TM-rich in the direction of the external magnetic field Hex (upward in the figure). Tc2 <T <Tc
At 4, the magnetization of the mask layer and the magnetic transfer layer is directed downward in the drawing by the RE-rich due to exchange coupling with the magnetization of the recording layer (however, in FIG. 17 (b), it is represented as the sublattice magnetization (upward) of the transition metal. ). Tcr4 <T <
At Tc2, the magnetization of the recording control layer appears in the same direction as the magnetization of the recording layer by exchange coupling, and at the same time, the magnetization state of the recording layer is firmly fixed by exchange coupling with the magnetization of the recording holding layer. When Tcr′5 <T <Tcr4, the magnetization of the mask layer 24a is directed from the perpendicular direction to the in-plane direction. Room temperature <T <Tc
At r′5, the magnetization of the magnetic transfer layer 24b is directed from the in-plane direction to the vertical direction. Thus, information is recorded on the recording layer. The above is the principle of recording on the magnetic recording medium 500.

Next, the principle of reproducing information recorded according to the above-described recording principle will be described. First, the case where the recording magnetic domain of the recording layer to be reproduced is formed downward as shown in FIG. Magnetic recording medium 5
While rotating 00 at a predetermined linear speed, the magnetic recording medium 500 is heated by irradiating a reproduction laser beam having a low laser power. By irradiating the magnetic recording medium 500 with a reproducing laser beam, the surface of the magnetic recording medium is heated with a temperature distribution as shown in the lower part of FIG. At this time, only the magnetization 180 in the temperature region of the mask layer 52 that is higher than the vertical temperature Tcr4 (150 ° C.) changes from the in-plane direction to the vertical direction. When the downward magnetization 181 is formed in the recording layer, the magnetization 180 of the mask layer 52 exchange-couples with the downward magnetization 181 of the recording layer located immediately below the mask layer 52 to reflect the magnetization state of the recording layer. Direction, ie, in FIG.
Turn downward.

The magnetization 182 in the temperature region of 150 ° C. or higher of the magnetic transfer layer 54 changes from the in-plane direction to the vertical direction, exchange-couples with the magnetization 180 of the mask layer 52, and reflects the magnetization state of the recording layer 5. That is, it faces downward in FIG. The magnetization 183 in the temperature region of the magnetic transfer layer 54 in the temperature range of in-plane temperature Tcr'5 (110 ° C.) or higher and lower than 150 ° C. changes from the perpendicular direction to the in-plane direction. At this time, the magnetization 183 of the magnetic transfer layer 54 becomes obliquely downward rightward as shown in FIG. 18 due to the magnetic field from the magnetization 181 of the recording layer 5 and the magnetization 184 of the recording control layer. The in-plane component of the magnetization of the magnetic transfer layer 54 obliquely downward and to the right is converted into an in-plane magnetization detection MR head 12.
Detected by 3 '. As described above, the downward magnetization of the recording layer is transferred to the magnetic transfer layer, and the information is reproduced by expanding the temperature to about the temperature region of the magnetic transfer layer in-plane temperature Tcr′5 (110 ° C.) or higher.

The above is the principle of reproduction when the recording magnetic domain to be reproduced is downward. Next, the case where the recording magnetic domain is directed upward will be described with reference to FIG.
In the same manner as described above, the reproduction laser beam
, The surface of the magnetic recording medium is heated with a temperature distribution as shown in the lower part of FIG. At this time, only the magnetization 190 in the temperature region of the mask layer 52 at a temperature higher than the perpendicular temperature Tcr4 (150 ° C.) changes from the in-plane direction to the vertical direction, and the upward magnetization 19 of the recording layer located immediately below the mask layer 52.
1 and is directed in a direction reflecting the magnetization state of the recording layer, that is, in the upward direction in FIG.

The magnetization 192 of the magnetic transfer layer 54 in the temperature region of 150 ° C. or more changes from the in-plane direction to the vertical direction, and exchange-couples with the magnetization 190 of the mask layer 52 to form the recording layer 5.
18, that is, in the upward direction in FIG. 18. The in-plane temperature Tcr′5 of the magnetic transfer layer 54 (110
19C), the magnetization 193 in the temperature region of not less than 150 ° C changes from the perpendicular direction to the in-plane direction, and is caused by the magnetic field from the magnetization 191 of the recording layer 5 and the magnetization 194 of the recording control layer, as shown in FIG. The magnetization becomes upward. This magnetic transfer layer 5
4, the in-plane component of the magnetization obliquely upward to the left is detected by the MR head 123 'for detecting the in-plane magnetization. In this way, the reproduction is performed while distinguishing the upward and downward magnetizations formed on the recording layer. The above is the principle of reproduction of the magnetic recording medium 500.

As described above, in the present embodiment, the magnetic domains of the recording layer 5 are independently enlarged and transferred to the magnetic transfer layer 54 via the mask layer 52, and the enlarged and transferred magnetic transfer is performed. Since the reproduction signal from the layer 54 is detected, a reproduction signal having a larger amplitude than the reproduction signal detected from the recording layer 5 can be obtained. Further, since information can be reproduced using an inexpensive MR head for detecting in-plane magnetization, the cost of drive manufacturing can be reduced.

Embodiment 5 Next, an embodiment in which information is reproduced using an inductive magnetic head instead of a magnetoresistive element will be described.

In this embodiment, as the magneto-optical recording medium, D
A magneto-optical recording medium (hereinafter, referred to as a DWDD medium) according to WDD (Domain Wall Displacement Detection) is used. FIG. 21 shows a cross-sectional structure of the magneto-optical recording medium 230 according to DWDD. DWDD medium 23
0 denotes a protective layer 232, a memory layer (recording layer) 233, and a switching layer 2 on the substrate 231, as shown in FIG.
34, a moving layer (reproducing layer) 235, a protective layer 236, and a lubricant layer 237 are sequentially laminated.

The substrate 231 is a polycarbonate substrate manufactured by an injection molding method, and is a land / groove type substrate having lands and grooves having a width of 0.6 μm.
The protective layer 232 provided on the substrate 231 is made of SiN and has a thickness of 60 nm. The memory layer 233 is a layer on which information is recorded, is made of TbFeCoCr, and has a thickness of 80 nm. The composition of TbFeCoCr of the memory layer 233 was adjusted so that the compensation temperature was about 80 ° C. and the Curie temperature was about 230 ° C.

The switching layer 234 is made of TbFeCr, and its composition is adjusted so that the compensation temperature is about 50 ° C. and the Curie temperature is about 110 ° C. The thickness of the switching layer 234 is 10 nm. Moving layer 235
Is composed of GdFeCr, and its composition is adjusted so that the compensation temperature is equal to or lower than room temperature and the Curie temperature is approximately 240 ° C. The thickness of the moving layer 235 is 30 nm. The protection layer 236 is made of SiN and has a thickness of 50 nm. These layers 232 to 236 are sequentially formed using a sputtering apparatus. The lubricant layer 237 formed on the protective layer 236 is a fomblin-based lubricant and has a thickness of 2
It is applied by a spin coat method in nm.

Here, the principle of the conventional reproduction method for the DWDD medium will be briefly described. For details of the reproduction principle, see, for example, “Proceedings of Magneto-Optical
Recording International Symposium '97, J.Magn.So
c.Jpn., Vol.22 Supplement No.S2 (1998), PP.47-50 ''
, Which can be referred to.

As shown in FIG. 22, when the DWDD medium is irradiated with the laser light 241, the DWDD medium is heated according to the temperature distribution of the laser light 241. Region 242 of switching layer 234 heated above Curie temperature Ts
In this case, the magnetization disappears, and the exchange coupling between the moving layer 235 and the memory layer 233 located above and below the magnetization is released. The region 242 where the magnetization of the switching layer 234 has disappeared is referred to as a bond disconnection region in the following description. When the DWDD medium is scanned with the light spot, the domain wall 243 (the boundary between the upward magnetic domain and the downward magnetic domain) enters the front boundary 245 of the coupling cutting region 242. In general, the force applied to the domain wall depends on the domain wall energy density, and the domain wall energy density is a function of temperature. Therefore, the force applied to the domain wall is generated by a temperature gradient around the domain wall. Therefore, as shown in the lower graph of FIG. 22, the force F is applied to the domain wall 243 from the low temperature side to the high temperature side in the track direction with the right direction being the plus direction.
(X) has occurred. Therefore, the domain wall 24 of the moving layer 235 that has lost the binding in the track direction due to the exchange coupling force.
3 moves to the position 246 of the peak temperature of the temperature distribution in the light spot by the force F (x). Since the moving speed of the domain wall 243 is faster than the moving speed of the medium, the magnetic domains of the upper moving layer 235 above the bond cutting region 242 expand in the track direction. As a result, the reproduction signal amplitude read from the moving layer 235 by the magneto-optical effect (Kerr effect) becomes larger than the reproduction signal amplitude when the magnetic domain recorded in the memory layer 233 is directly read. That is, the memory layer 23
Even if the magnetic domain recorded in No. 3 is minute, it can be reproduced by a reproduced signal obtained by amplifying it.

When isolated magnetic domains recorded on the DWDD medium are subjected to conventional magneto-optical reproduction, two reproduced waveforms are observed as shown in FIG. 23. The mechanism will be described with reference to FIGS.
Note that the numbers (1) to (4) shown in FIG.
(1) to (4). Less than,
The situations (1) to (4) will be briefly described. (1)
When the magnetic domain wall 252 on the left side of the isolated magnetic domain (upward magnetic domain) 251 of the moving layer 235 enters the position of the front boundary 245 of the coupling cutting region 242, the magnetic domain wall 252 is formed in the moving layer 235 according to the above-described principle. Move leftward toward peak temperature. (2) When the DWDD medium moves relative to the light spot and the domain wall 253a on the right side of the isolated magnetic domain 253 of the memory layer 233 enters the position of the front boundary 245 of the coupling cut region, the domain wall 252 in the moving layer 235 Moves leftward in the figure to the position of the peak temperature in the temperature distribution. (3) When the DWDD medium further moves with respect to the light spot, the domain wall 253b on the left side of the isolated magnetic domain 253 of the memory layer 233 becomes the rear boundary portion 247 of the coupling cut region.
Pass through. The portion of the isolated magnetic domain 253 of the memory layer 233 that has passed through is transferred to the moving layer 235 by exchange coupling in a region on the left side of the coupling cut region. The domain wall 254 located on the right side of the rear boundary portion 247 of the moving layer 235 moves rightward toward the position of the peak temperature. (4) DWD
When the D medium moves with respect to the light spot, the memory layer 23
The right magnetic domain wall 253a of the third isolated magnetic domain 253 passes through the rear boundary portion 247 of the coupling cut region, and the downward magnetic domain (space) 255 of the memory layer 233 in the portion where the domain wall 253a has passed passes through the moving layer 235 by exchange coupling on the left side of the coupling cut region. Is transferred to
Then, the domain wall 2 in the moving layer 235 at the rear boundary portion 247
56 moves rightward toward the peak temperature. This indicates that two reproduced signals are observed for one isolated magnetic domain to be read. In FIG.
The reproduced signals (1) and (2) are reproduced signals to be read, and the reproduced signals (3) and (4) are unintended reproduced signals. The reproduced signals (3) and (4) are called ghost signals. Thus, it is not preferable that two reproduced signals are observed from one isolated magnetic domain. This is because if the interval between magnetic domains becomes narrower for further densification, it becomes difficult to distinguish these reproduced signals individually. In the present embodiment, such a problem could be effectively prevented by reproducing using an inductive magnetic head as described later. Hereinafter, an example in which information recorded on a DWDD medium is reproduced using an inductive magnetic head will be described.

FIG. 25 shows a DW using an induction type magnetic head.
FIG. 3 shows a conceptual diagram of how a DD medium is reproduced. As shown in the figure, the optical system is arranged so that the laser beam is incident on the substrate 231 side of the DWDD medium 230, and the inductive magnetic head 260 is arranged at a position facing the optical system via the medium 230. You. The optical system includes a laser light source (not shown) that emits laser light having a wavelength λ = 680 nm,
An objective lens having a numerical aperture NA = 0.55 is provided. Focusing and tracking servo can be performed by irradiating the medium with such laser light and detecting light reflected from the medium.

The induction type magnetic head 260 has a core 261
(Magnetic core) and a single magnetic pole contact type magnetic head including a coil 262. The core 261 can be configured using, for example, permalloy. The portion of the core 261 that comes into contact with the medium has a dimension in the track width direction of about 1.0 μm and a length in the track direction (hereinafter, referred to as a head length) of about 0.5.
It is processed to a thickness of μm. The number of turns of the coil 262 is 100. The inductive magnetic head 260 can record a recording magnetic domain in the memory layer by generating a recording magnetic field during information recording. Further, at the time of reproducing information, it is possible to reproduce information by changing a change in a leakage magnetic field from a recording magnetic domain into an electric signal using an electromotive force due to electromagnetic induction.

The reproduction output e of the induction type magnetic head 260 is
Assuming that the number of turns of the coil is N, the magnetic flux is Φ, and the time is t, e = −N (dΦ / dt). When this expression is further modified, e = −N (dΦ (x) / dx) (dx / dt) = N (dΦ / dx) v (1) v is a relative moving speed (linear velocity) of the medium with respect to the inductive magnetic head.

In the present embodiment, it is assumed that information is recorded on the land of the DWDD medium 230.
Unclosed domain wal in the memory layer
l) The magnetic properties of the groove memory layer were degraded by annealing the groove memory layer to form a recording magnetic domain. The annealing conditions were as follows: linear velocity v = 1.5 m / s,
The annealing laser power Pa was set to 10.0 mW. 26 shows the distribution in the track direction of the magnetic flux Φ interlinking with the coil of the induction type magnetic head when continuous magnetic domains are formed in the DWDD medium. The reproduced signal output when such a continuous magnetic domain is reproduced has a waveform similar to the waveform shown in the lower part of the figure according to the above equation (1).

Next, a 0.8 μm
Were recorded by the magnetic field modulation method. The recording conditions were as follows: linear velocity v = 1.5 m / s, recording power Pw = 3.0 m
W, the recording magnetic field Hw = ± 400 Oe. The recording magnetic domain was reproduced using an induction type magnetic head while irradiating the recording medium with a laser beam. FIG. 27 shows the reproduction output (Δx = 0.2 μm). In FIG. 27, the solid line represents the reproduction laser power Pr.
= 1.0 mW indicates a reproduction output at the time of normal reproduction,
Dotted line is DWD at reproduction laser power Pr = 1.7mW.
This is a playback output when D playback is performed. Here, the normal reproduction means that the magnetic domain of the memory layer is transferred to the moving layer through the switching layer by exchange coupling without moving the magnetic domain of the memory layer because the temperature of the switching layer is equal to or lower than the Curie temperature thereof. In a layer, information is reproduced without causing domain wall motion. DWDD reproduction is a method in which a coupling / disconnection region is formed in a switching layer, and information is reproduced by generating magnetic motion in the moving layer as described above. This is the playback method used.

In normal reproduction, "v" in the above equation (1) corresponds to a linear velocity of 1.5 m / s. On the other hand, in DWDD reproduction, "v", that is, the domain wall moving speed becomes several tens times or more of that. Therefore, as shown in FIG. 27, in the DWDD reproduction, the reproduction output becomes larger and the half width of the reproduction signal waveform becomes smaller than in the normal reproduction. This is because, in terms of the resolution in the track direction, the DW
DD reproduction has been shown to be extremely effective as a method of reproducing information recorded at high density.

Next, it was examined how the reproduction signal changes by changing the relative position (Δx) of the center of the core of the induction type magnetic head to the center of the light spot. In FIG.
6 shows the Δx dependence of the reproduction output when DWDD reproduction is performed on a 0.8 μm isolated magnetic domain. As shown in the figure, the reproduction signal was observed by disposing the center of the core of the induction type magnetic head at a position shifted by Δx from the center of the light spot. Here, the right side in the figure is plus and the left side is minus. When Δx = −0.2 μm, that is, when the core center is on the left side (rear side in the medium moving direction) of the center of the light spot, a ghost signal was observed. on the other hand,
It can be seen that when Δx is large, that is, when the center of the core is on the right side (front side in the medium moving direction) of the center of the light spot, the amplitude of the ghost signal decreases and eventually disappears. This means that the ghost signal can be suppressed if the center of the core of the magnetic head is between the front boundary portion of the coupling cutting region and the peak temperature position in FIG.

In DWDD reproduction, domain wall motion occurs in the moving layer toward a position where the temperature reaches a peak in a temperature distribution generated by irradiating a laser beam. Δ
When x = −0.2 μm to 0.1 μm, it is considered that a ghost signal was observed because a peak temperature was located immediately below the core of the inductive magnetic head. On the other hand, Δx
If ≧ 0.2 μm, the peak temperature position is outside the core, and it can be considered that no ghost signal is observed.

As described above, by reproducing (DWDD reproduction) the DWDD medium by using the induction type magnetic head, it is possible to obtain a reproduction output larger than that of the normal reproduction, and furthermore, it is possible to suppress a decrease in resolution due to high density recording. We were able to. Also, the head length of the core of the induction type magnetic head is set to about half of the diameter of the light spot, and the position of the core is located forward of the center of the light spot in the medium traveling direction (right side in FIG. 28).
Ghost signals could be suppressed.

As described above, the present invention has been specifically described with reference to the drawings. However, the present invention is not limited to the above-described first to fifth embodiments, but includes modifications and improvements conceivable by those skilled in the art. Nor. For example, the distance between the substrate 1 and the recording auxiliary layer 2 in the first and second embodiments and the third and fourth embodiments.
A base layer for controlling magnetic anisotropy may be provided between the substrate 1 and the recording holding layer 3 in the above.

[0097]

According to the magnetic recording medium of the present invention, the recording layer is composed of a ferrimagnetic material having perpendicular magnetization.
By applying a recording magnetic field while applying heat to a predetermined area of the medium, information can be recorded at an extremely high density. In addition, since the recording layer has a large coercive force of 5 kOe or more at room temperature, even when minute recording marks are formed on the recording layer, disappearance of the recording marks due to thermomagnetic relaxation phenomenon is prevented or suppressed.

According to the recording method of a magnetic recording medium of the present invention, while applying heat to a magnetic recording medium having a recording layer having perpendicular magnetization, the width of the magnetic pole in the direction perpendicular to the recording direction is 1 μm or less. Since recording can be performed at a high density by using a certain magnetic head, it is very suitable as the recording method of the magnetic recording medium of the present invention.

Further, according to the reproducing method of the magnetic recording medium of the present invention, while the heat is applied to the magnetic recording medium, the information perpendicularly recorded on the magnetic recording medium can be used for the magnetic element having a magnetoresistive element or a spin valve film. Since it can be reproduced using an inductive magnetic element, it is suitable as a method for reproducing the magnetic recording medium of the present invention.

The recording / reproducing head of the present invention includes a heat source for heating the magnetic recording medium, a magnetic field generating source and a magnetic element mounted on the air slider, and uses the heat source to control the magnetic recording medium. While heating, information can be recorded at a high density using a magnetic field source mounted on the air slider. As the magnetic element, for example, a magnetic element having a magnetoresistive element, a spin valve film, or an inductive magnetic element can be used. Further, since information recorded at high density can be reproduced using these magnetic elements, it is suitable as the recording / reproducing head of the magnetic recording medium of the present invention.

According to the recording method of an information recording medium of the present invention, a light spot is projected onto an information recording medium having a recording layer having perpendicular magnetization, and the light spot is projected to a region inside the light spot. Since a recording mark can be formed, it is very suitable as a recording method for an ultra-high density information recording medium.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a specific example of a magnetic recording medium according to the present invention.

FIG. 2 is a schematic sectional view of a specific example of a recording / reproducing head according to the present invention.

FIG. 3 is a diagram showing a temperature characteristic of a coercive force of a recording layer of a magnetic recording medium according to the present invention.

FIG. 4A is a diagram showing an outline of a recording / reproducing experiment on a magnetic recording medium, and FIG. 4B is a cross-sectional view of an arrangement of a magnetic recording medium and a recording / reproducing head.

FIG. 5 is a diagram illustrating a recording principle of the magnetic recording medium shown in FIG.

FIG. 6 is a graph showing the environmental durability of the S / N ratio of the magnetic recording medium according to the present invention.

FIG. 7 is a graph comparing the environmental durability of the S / N ratio between a magnetic recording medium according to the present invention and a conventional magnetic recording medium.

FIG. 8 is a graph showing a change in reproduction output with respect to a recording mark length of a magnetic recording medium.

FIG. 9 is a schematic sectional view of a magnetic recording medium according to the present invention manufactured in Example 2.

10 is a graph showing temperature characteristics of saturation magnetization of the reproducing layer and the recording layer of the magnetic recording medium shown in FIG.

FIG. 11 is a diagram illustrating a recording principle of the magnetic recording medium shown in FIG.

FIG. 12 is a schematic sectional view of a magnetic recording medium according to the present invention manufactured in Example 3.

FIG. 13 is a schematic sectional view of a recording / reproducing head according to the present invention used in Example 3.

FIG. 14 is a diagram illustrating a recording principle of the magnetic recording medium shown in FIG.

FIG. 15 is a diagram illustrating the principle of reproduction of the magnetic recording medium shown in FIG.

FIG. 16 is a schematic sectional view of a magnetic recording medium manufactured in Example 4 according to the present invention.

FIG. 17 is a diagram illustrating a recording principle of the magnetic recording medium shown in FIG.

FIG. 18 is a view for explaining the principle of reproduction when a downward recording magnetic domain is formed in the recording layer of the magnetic recording medium shown in FIG.

FIG. 19 is a diagram for explaining the principle of reproduction in the case where upward recording magnetic domains are formed in the recording layer of the magnetic recording medium shown in FIG.

FIG. 20 is a diagram schematically showing a cross-sectional structure of a single-pole head.

FIG. 21 is a schematic sectional view of a magneto-optical recording medium according to DWDD manufactured in Example 5.

FIG. 22 is a diagram for explaining a basic principle in a conventional reproduction method of a DWDD medium.

FIG. 23 is a reproduction waveform when an isolated magnetic domain is subjected to conventional magneto-optical reproduction, and shows a state where two reproduction waveforms are observed.

FIG. 24 is a diagram for explaining states (1) to (4) of the reproduced waveform shown in FIG. 23;

FIG. 25 is a conceptual diagram showing how a DWDD medium is reproduced using an inductive magnetic head.

FIG. 26 is a diagram showing a distribution of a magnetic flux Φ interlinking with a coil of an induction type magnetic head in a track direction and a reproduction signal output when a continuous magnetic domain is formed in a DWDD medium.

FIG. 27 shows a reproduction output when a continuous magnetic domain is normally reproduced,
It is a figure which shows the reproduction output at the time of DWDD reproduction.

FIG. 28 is a diagram illustrating a state where a reproduction signal changes by changing a relative position (Δx) of a core center of the induction type magnetic head with respect to a light spot center.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording auxiliary layer 3 Recording holding layer 4 Recording control layer 5 Recording layer 50 Reproduction layer 52 Mask layer 54 Magnetic transfer layer 20, 120 Head main body part 22, 122 Recording magnetic head 23, 123 Reproduction MR head 27, 127 Laser light source 31 Heat source 100, 300, 400, 500 Magnetic recording medium 200, 210 Recording / reproducing head

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 11/105 586 G11B 11/105 586N (72) Inventor Sho Imai 1-88, Ushitora 1-chome, Ibaraki-shi, Osaka No. Within Hitachi Maxell Co., Ltd. (72) Hiroyuki Awano, Inventor Hiroyuki Awano 1-1-88 Ushitora, Ibaraki City, Osaka Prefecture Inside Hitachi Maxell Co., Ltd. (72) Yuji Yamazaki 1-1-88 Ushitora, Ibaraki City, Osaka Prefecture, Hitachi Maxell, Inc.

Claims (39)

[Claims] 1. A magnetic recording medium, comprising: a substrate; a recording holding layer made of a magnetic material; and a recording layer made of a ferrimagnetic material having perpendicular magnetization. By applying a recording magnetic field while heating the area, the recording magnetic domain of the recording layer is reversed to record information, and the information is reproduced by detecting the magnetic field from the recording magnetic domain of the recording layer. recoding media. 2. The recording layer has a Curie temperature of 300 ° C.
The magnetic recording medium according to claim 1, wherein the magnetic recording medium has a coercive force of 5 kOe or more in a temperature range of 10 to 100 ° C and a coercive force of 2 kOe or more at 200 ° C or more. 3. The magnetic recording medium according to claim 1, wherein the recording holding layer is formed using a ferrimagnetic material. 4. The magnetic recording medium according to claim 1, wherein the recording holding layer is formed using an antiferromagnetic material. 5. The magnetic recording medium according to claim 1, wherein the recording holding layer exists between the substrate and the recording layer. 6. The recording layer according to claim 1, further comprising a reproducing layer having a higher saturation magnetization than the recording layer in a temperature range of 20 ° C. to 150 ° C. A magnetic recording medium according to claim 1. 7. The magnetic recording medium according to claim 6, wherein a recording magnetic domain of a recording layer is transferred to the reproducing layer. 8. The magnetic recording medium according to claim 1, further comprising a recording auxiliary layer exhibiting soft magnetism. 9. The magnetic recording medium according to claim 1, wherein the substrate is made of a plurality of materials having different thermal conductivities. 10. A recording method for recording information on a magnetic recording medium having a recording layer on a substrate, wherein while applying heat to a predetermined area of the magnetic recording medium, the intensity is determined using a magnetic head according to the information to be recorded. And information is recorded by applying a magnetic field in which at least one of the directions is modulated, wherein the recording layer is formed using a ferrimagnetic material having perpendicular magnetization, and in a direction perpendicular to the recording direction of the magnetic head. A recording method for a magnetic recording medium, wherein the width of the magnetic pole is 1 μm or less. 11. The recording method for a magnetic recording medium according to claim 10, wherein light is applied to apply heat to a predetermined area of the magnetic recording medium. 12. The recording method for a magnetic recording medium according to claim 11, wherein an optical fiber is used for irradiating the light. 13. The recording method for a magnetic recording medium according to claim 11, wherein light is focused on a surface of the magnetic recording medium using an objective lens. 14. A method according to claim 1, wherein a heater is used to apply heat to a predetermined area of the magnetic recording medium, and the heat from the heater is conducted by heat conduction to a position of 1 μm or less from the surface of the magnetic recording medium. 11. The recording method for a magnetic recording medium according to item 10. 15. The recording method for a magnetic recording medium according to claim 10, wherein the magnetic head is a single-pole head. 16. The method according to claim 10, wherein a series of information is divided and recorded simultaneously at a plurality of positions on a magnetic recording medium using a plurality of magnetic heads. Recording method of a magnetic recording medium. 17. A reproducing method for reproducing information recorded on a magnetic recording medium having a recording layer, wherein the recording layer is made of a ferrimagnetic material having perpendicular magnetization, and has a magnetoresistive element and a spin valve film. A method for reproducing a magnetic recording medium, comprising reproducing information recorded on a recording layer using a kind of magnetic element selected from the group consisting of an element and an inductive magnetic element. 18. The recorded information is recorded by applying heat to a predetermined area of a magnetic recording medium and applying a magnetic field having at least one of intensity and direction modulated according to the recorded information. 18. The method of claim 17, wherein
3. A method for reproducing a magnetic recording medium according to claim 1. 19. The magnetic recording medium according to claim 1, further comprising: a reproducing layer on the recording layer, the reproducing layer having a higher saturation magnetization than the recording layer in a temperature range of 20 ° C. to 150 ° C., and reproducing the magnetic recording medium. 19. The information is reproduced by applying heat to the region to transfer the magnetization of the recording layer to the reproduction layer, and detecting the transferred magnetization of the reproduction layer by using the magnetic element. 3. A method for reproducing a magnetic recording medium according to claim 1. 20. A series of information is recorded at a plurality of positions on a magnetic recording medium, and the information recorded at the plurality of positions is simultaneously reproduced using a plurality of magnetic elements. The method for reproducing a magnetic recording medium according to any one of claims 17 to 19, wherein: 21. A method for recording information on an information recording medium provided with a recording layer having perpendicular magnetization on a substrate, comprising: irradiating the information recording medium with a light spot; A method for recording information on an information recording medium, characterized in that information is recorded by applying a magnetic field only to a smaller area. 22. The recording method according to claim 21, wherein a magnetic field is applied to an area smaller than the light spot using a single-pole head. 23. A recording and / or reproducing head for a magnetic recording medium, comprising: a magnetic field source for applying a recording magnetic field to the magnetic recording medium; and a magnetic element for reading magnetization information of the magnetic recording medium. A magnetic element selected from the group consisting of a magnetic element having a spin-valve film and a magnetoresistive element, and an inductive magnetic element; and an air slider on which the magnetic field generating source and the magnetic element are mounted. Record and / or
Or a playback head. 24. The recording and / or reproducing head according to claim 23, further comprising a heat source for heating the magnetic recording medium. 25. The recording and / or reproducing head according to claim 24, wherein the heat source is a laser light source, and the magnetic recording medium is heated by laser light emitted from the laser light source. 26. The recording and / or reproducing head according to claim 23, wherein the air slider is made of a plurality of materials having different thermal conductivities. 27. A circuit between the magnetic field generating source and a magnetic element,
27. The recording and / or reproducing head according to claim 26, wherein the recording and / or reproducing head is made of a material having a low thermal conductivity among the plurality of materials having different thermal conductivity. 28. A circuit between the magnetic field generating source and a magnetic element,
27. The recording and / or reproducing head according to claim 26, wherein a material having a high thermal conductivity is used among the plurality of materials having different thermal conductivity. 29. The recording and reproducing apparatus according to claim 24, wherein the magnetic field generating source, the magnetic element, and the heat source are all arranged on one surface side of a magnetic recording medium. And / or playback head. 30. The recording according to claim 24, wherein the magnetic field generating source, the magnetic element, and the heat source are arranged to face each other via a magnetic recording medium. And / or a reproducing head. 31. When performing recording or reproduction while moving a magnetic recording medium with respect to a head, a heat source is disposed in the front of the moving direction of the magnetic recording medium, and a magnetic element is disposed in the head in the rear. 3. The method according to claim 2, wherein
31. The recording and / or reproducing head according to any one of 4 to 30. 32. The magnetic element is an inductive magnetic element, and when performing recording or reproduction while moving the magnetic recording medium with respect to the head, the magnetic element is located on the front side in the moving direction of the magnetic recording medium and on the rear side. 25. The recording and / or reproducing head according to claim 24, wherein the heat sources are respectively arranged in the head. 33. The magnetic recording medium is a recording medium comprising at least a magnetic layer having a magnetic property in which a domain wall of a magnetic domain moves in an in-plane direction according to a heat distribution formed by heat from a heat source. A recording and / or reproducing head according to claim 32. 34. The recording and / or reproducing head according to claim 23, wherein the magnetic field generating source is constituted by a single pole head. 35. The recording and / or reproducing head according to claim 34, wherein at least a part of the single pole head is made of a material having a saturation magnetic flux density of 2.0 T or more. 36. A magnetic field generating section of the single pole head,
36. The recording and / or reproducing head according to claim 35, wherein the recording and / or reproducing head is made of a material having a saturation magnetic flux density of 2.0 T or more. 37. The recording and / or recording apparatus according to claim 35, wherein the material having a saturation magnetic flux density of 2.0 T or more is CoNiFe or an alloy containing the same.
Or a playback head. 38. The magnetic recording medium has a plurality of tracks, and the single pole head is configured by winding a coil around a core,
The recording and / or reproducing head according to any one of claims 34 to 37, wherein a width of a leading end portion of the core in a track width direction is 1 m or less. 39. The information recording medium has a recording layer on a substrate, and the recording layer is made of a ferrimagnetic material having perpendicular magnetization, and the recording magnetic field is heated while heating a predetermined area of the magnetic recording medium. 24. The magnetic recording medium according to claim 23, wherein the information is recorded by inverting a recording magnetic domain of the recording layer by applying the information, and the information is reproduced by detecting a magnetic field from the recording magnetic domain of the recording layer. 2. The recording and / or reproducing head according to claim 1.