JPH02201726A - Superconducting magnetic recording medium and production thereof and recording method - Google Patents

Abstract

PURPOSE:To induce perpendicular magnetic moments by the annular current generated in the superconducting microrings constituting recording units by providing a recording layer arranged with the above-mentioned microrings on a substrate and impressing external magnetic fields to the respective superconducting microrings. CONSTITUTION:The many microrings 12 are arranged and disposed along track lines on the disk substrate 14. A nonmagnetic film 22 or a magnetic film 24 consisting of a soft magnetic material is formed to cover the ultra-microrings 12 and the layer consisting of the microrings 12 and the nonmagnetic film 22 or magnetic film 24 is used as the recording layer 26. A protective film is thereafter formed on the outside surface, by which the magnetic recording medium 10 is produced. The perpendicular magnetic moments can be generated and recorded in the respective microrings 12 by passing the magnetic recording medium 10 in the impressed magnetic fields. The induction of the perpendicular magnetic moments by the annular currents generated in the microrings 12 is enabled in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a superconducting magnetic recording medium and a method for manufacturing the same, and particularly relates to a computer recording memory, a memory card,
The present invention relates to a superconducting magnetic recording medium that can be applied to other magnetic recording media and a method for manufacturing the same.

[Conventional technology]

Conventionally, recording media such as recording memories and memory cards for personal computers have been magnetic recording media using magnetic materials, such as magnetic tapes, floppy disks, hard disks, magnetic cards, and magneto-optical disks. This type of magnetic recording medium is manufactured by laminating a magnetic layer and a protective layer on a substrate, and records are made by applying a magnetic field to each magnetic domain of the magnetic layer using a magnetic field or the like. In this case, there are magnetic recording media that use a method of horizontal magnetization and a method of perpendicular magnetization and optical detection, but in both cases the magnetic layer is directly magnetized.

[Problems to be solved by the invention]

However, the above conventional magnetic recording media such as floppy disks and hard disks have a problem in that magnetic properties such as coercive force and magnetic moment are limited depending on the magnetic material used, and cannot be changed freely. . Furthermore, since the usable magnetic materials are limited, there is a drawback that a high coercive force cannot be obtained.

Moreover, the magnetization direction may become unclear at the boundaries of magnetic domains, and there is also the problem that the recording density cannot be sufficiently increased.

An object of the present invention is to provide a superconducting magnetic recording medium, a method for producing the same, and a recording method for the same, which can sufficiently divide signals even with increased coercive force and recording density, and increase the degree of freedom of recorded signals. shall be.

More specifically, by placing a microring made of superconducting material on a substrate such as a tape or disk and using it as a magnetic medium, the direction and magnitude of the perpendicular magnetic moment can be freely controlled by changing the external magnetic field. Allows for change. In addition, by arranging this microring in a magnetic medium, it is possible to easily generate a perpendicular magnetic moment, making it possible to use soft magnetic materials as a recording medium, which until now could not be used as a magnetic recording medium. It is something to do.

[Means for Solving the Problem] In order to achieve the above object, a superconducting magnetic recording medium according to the present invention includes a recording layer in which superconducting material micro-rings constituting recording units are arranged on a substrate, and each of the superconducting By applying an external magnetic field to the material microring, a perpendicular magnetic moment can be induced by a circular current generated in the microring. Furthermore, a soft magnetic material may be provided at least within the superconducting material microring of the recording layer. Furthermore, it is also possible to form a multilayer structure by forming two or more recording layers containing the superconducting microrings.

Further, the method for manufacturing a superconducting magnetic recording medium according to the present invention includes:
After forming a superconducting film on a substrate by vapor deposition, a large number of remaining micro rings are arranged by photoresist and etching.
A recording layer is formed by forming a nonmagnetic film or a magnetic film around this microring, and a protective film is formed on the outer layer of the recording layer.

Furthermore, the recording method of the superconducting magnetic recording medium according to the present invention includes:
A perpendicular magnetic moment is induced by applying an external magnetic field according to a recording signal to each of the microrings of a superconducting magnetic recording medium, which has a recording layer in which microrings of superconducting material constituting recording units are arranged on a substrate. Recorded signals can be reproduced using a magnetic head. In addition, after inducing a perpendicular magnetic moment by applying a uniform external magnetic field to a superconducting magnetic recording medium, which has a recording layer in which superconducting material microrings constituting recording units are arranged on a substrate, The perpendicular magnetic moment is erased by irradiating the ring with a laser beam to break the superconductivity, and a digital signal is generated depending on the presence or absence of the perpendicular magnetic moment.

[Effect]

According to this invention, by applying a vertical external magnetic field to a microring made of a superconducting material, a circular current flows through the microring according to the right-handed screw rule. Even after removing the vertical external magnetic field, the microannulus remains
Due to the superconducting phenomenon, a circular current flows and a perpendicular magnetic moment remains, which is used for magnetic recording. A soft magnetic material, which until now could not be used as a recording medium due to its small coercive force, can be given a higher coercive force by using it as a recording medium in combination with this microring. Further, by forming a multilayer recording layer containing superconducting material micro-rings so that the micro-rings do not overlap with each other, the recording density can be greatly improved. The superconducting magnetic recording medium is produced by forming a superconducting film by physically or chemically depositing a superconducting material on a substrate, and then applying a photoresist or a superconducting film to the substrate.
Desired micro-rings can be easily formed by etching or the like. Therefore, it is possible to manufacture a magnetic recording medium having a superconducting material microring very easily. Also,
By applying an external magnetic field based on a recording signal to the magnetic recording medium, a perpendicular magnetic moment is generated in each superconducting microring according to the direction and magnitude of the applied magnetic field, and this is read by a magnetic head. You can record and play back. In addition, if a magnetic recording medium is placed in a uniform external magnetic field in advance to generate a ring current, and a laser beam is irradiated onto a predetermined micro ring in response to a digital signal, the superconducting state is destroyed and the vertical current is generated. The magnetic moment disappears.

Therefore, digital signals can be recorded on the magnetic recording medium depending on the presence or absence of the perpendicular magnetic moment. The reading can be identified by the Kerr effect or Faraday effect.

〔Example〕

EMBODIMENT OF THE INVENTION Below, specific examples of a superconducting magnetic recording medium, its manufacturing method, and a recording method according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partial perspective view of a superconducting magnetic recording medium IO according to an example. As shown in this figure, a superconducting magnetic recording medium 10 has a large number of superconducting micro-rings 12 arranged on a disk substrate 14 in alignment along a spiral line. The micro ring 12 is made of a superconducting material such as yttrium-based or thallium-based oxide, and has a diameter as small as micrometers.

Such a magnetic recording medium 10 is manufactured by the method shown in FIG. That is, a superconducting material such as yttrium-based or thallium-based oxide is diffused and deposited on one side of the disk substrate 14 by PVD, CVD, or sputtering. After growing this superconducting film 16 to several micrometers, a photoresist 18 such as an ultraviolet curable resin is formed, and this photoresist 18 is irradiated with ultraviolet rays corresponding to the micro rings 12 to harden it into a ring shape. form. Needless to say, a large number of these are formed at a predetermined pitch along the track line to be formed on the disk substrate 14.

After forming this mold 20, the superconducting film 16 is etched, and superconducting material micro-rings 1 are etched corresponding to the mold 20.
2 remains. A large number of micro-rings 12 are arranged along the track line on the disk substrate 14, and a non-magnetic film 22 or a magnetic film 24 made of soft magnetic material is formed to cover the micro-rings 12. Microcircle 12
A recording layer 26 is composed of a nonmagnetic film 22 or a magnetic film 24. Thereafter, a protective film 28 is formed on the outer surface, and the magnetic recording medium 10 is manufactured.

By passing the thus formed magnetic recording medium 10 through an applied magnetic field, a perpendicular magnetic moment 30 can be generated and recorded in each microring 12. That is, as shown in FIG. 3, a recording signal current is input, thereby causing a signal magnetic field line 32 to be generated in the direction of the center of the micro ring 12 (in the vertical direction in the figure), and the recording means 34 is moved along the track line. .

Due to the magnetic field applied by the recording means 34, a ring current flows in the micro ring 12 due to an induced electromotive force, and this causes a ring current to flow through the micro ring 12.
Since 2 is made of superconducting material, it is stored as a persistent current. In this case, since the superconducting phenomenon is currently occurring under a constant cooling condition, these series of processes are carried out in a cooling system as shown in FIG. Of course, if a room-temperature superconducting material is obtained, this can be done outside the cooling system. A perpendicular magnetic moment 30 is generated in the micro ring 12 through which a permanent ring current is passed in this way according to the right-handed screw law, and this has a different direction and magnitude depending on the signal magnetic field lines 32, and this corresponds to the recorded signal. (See Figure 5).

To reproduce signals using the magnetic recording medium 10 recorded in this manner, the magnetic head 36 may be used. That is, as shown in FIG. 5, the magnetic head 36 may be made to correspond to the track line of the magnetic recording medium 10, and the two may be moved relative to each other. The vertical MA moment 30 recorded and held in each micro ring 12 of the recording layer 26 is transferred to the magnetic head 36.
An output current corresponding to the direction and magnitude of magnetization flows through the coil, and thereby the recorded content can be detected from the magnetic head 36.

Such a magnetic recording medium 10 and its drive unit 3
8 is housed in a cooling box 40, as shown in FIG. 6, to prevent destruction of the superconducting phenomenon.

According to the magnetic recording medium 10 configured in this way, the recording layer 26 including the superconducting material micro-rings 12 is formed on the disk substrate 14, and the perpendicular magnetic moment is created by flowing a ring current based on the recording signal through each micro-ring 12. 30, the boundaries of the magnetic domains become clear and a high coercive force can be obtained even when the recording density is increased. In particular, since a soft magnetic material can be used for the magnetic film 24, the start-up performance during recording is improved and the coercive force is further improved.

Next, FIGS. 7 and 8 show examples of magnetic recording media 10A and IOB in which the recording layer 26 has a multilayer structure. The magnetic recording medium 10A shown in FIG. 7 has a two-layer recording layer 26, with the upper and lower micro-rings 12 arranged concentrically, and the magnetic recording medium 10B shown in FIG. 8 has the upper and lower micro-rings 12 arranged concentrically. The arrangement is such that the positions are shifted in the track line direction to prevent overlapping. In the former case, the strength of the perpendicular magnetic moment 30 can be increased to facilitate reproduction, and in the latter case, the number of micro-rings 12 per unit track can be increased to increase the recording density.

In FIG. 9, the recording method for the magnetic recording medium 10 is changed so that it can be used as a magneto-optical recording medium. This recording method places the magnetic recording medium 10 described above in a uniform applied magnetic field 44 generated by an applying magnet 42, thereby generating a circular current in each microring 12 and aligning the directions of the perpendicular magnetic moments 30. . Then, using a laser emitting device 46 as a recording device,
A predetermined micro ring 12 is irradiated with a laser beam while the magnetic recording medium 10 is rotated. Micro ring 12 irradiated with laser light
is heated above the superconducting critical temperature, the superconducting state is destroyed and it becomes a normal conducting state. As a result, the micro ring 12 irradiated with the laser beam becomes a so-called bit 48, which is recorded as a digital signal depending on the presence or absence of the perpendicular magnetic moment 30.

When reproducing the magneto-optical recording medium 10 recorded in this manner, the recorded information is read out using the Kerr effect and the Faraday effect, in which reflected or transmitted laser light is polarized depending on the presence or absence of the perpendicular magnetic moment 30. As shown in FIG. 10, the laser beam 54 emitted from the laser light source 52
is reflected by each micro ring 12 through a polarizer 55, passed through an analyzer 56, and detected by a light detection element 58. However, if there is a perpendicular magnetic moment 30, the polarization plane of the reflected light changes by an angle θ. When it rotates and the vertical magnetic moment 30 is demagnetized, it becomes θ-0.

Therefore, it is possible to distinguish between "1" and "0" by the value of θ,
This makes it possible to detect signals recorded as digital signals.

When erasing the record on the magneto-optical recording medium IO, the first
As shown in FIG. 1, the application magnet 42 may be scanned to generate a perpendicular magnetic moment 30 in all the micro-rings 12.

The magnetic film 24 constituting the recording layer 26 of the magneto-optical recording medium 10 is made of yttrium iron garnet (YTG) with a large amount of Bi substituted, rare earth iron garnet (GIG), etc.
Use. This particularly has the effect of increasing the Welde constant and facilitating regeneration using the Faraday effect.

〔Effect of the invention〕

As explained above, according to the present invention, it can be used as a new magnetic recording medium that has a perpendicular magnetic moment whose size direction can be freely changed due to superconducting material microrings, and it can also be used in combination with conventional magnetic media. This makes it possible to generate a perpendicular magnetic moment with excellent rise, and allows the use of soft magnetic materials. Depending on the recording method, it can also be used as a magneto-optical recording medium, and can be used as a magneto-optical recording medium that can be easily recorded and reproduced while achieving particularly high recording density, and can be erased and overridden. That is, the present invention provides a superconducting magnetic recording medium, a method for manufacturing the same, and a recording method for the same, in which sufficient signal division is possible even with increased coercive force and recording density, and the degree of freedom of recorded signals is increased. A micro ring made of superconducting material is placed on a substrate such as a tape or disk and used as a magnetic medium, and by changing the external magnetic field, it is possible to freely change the direction and magnitude of the perpendicular magnetic moment. Become. In addition, by arranging this microring in a magnetic medium, it is possible to easily generate a perpendicular magnetic moment, making it possible to use soft magnetic materials as a recording medium, which until now could not be used as a magnetic recording medium. Become.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of a magnetic recording medium according to an embodiment, and FIG.
The figure is an explanatory diagram of the manufacturing method, Part 3 is an explanatory diagram of the state in which a circular current is generated in the magnetic recording medium, Figure 4 is an explanatory diagram of the state in which the perpendicular magnetic moment is generated by the circular current, and Figure 5 is the magnetic recording medium FIG. 6 is an explanatory diagram of the cooling system, FIG. 7 is a partial cross-sectional view of a modified embodiment in which the recording layer of the magnetic recording medium is multilayered, and FIG. 8 is a further example of another multilayer structure. FIG. 9 is an explanatory diagram of the recording method when the magnetic recording medium is used as a magneto-optical recording medium, FIG. 10 is an explanatory diagram of the principle behind the successive development of magneto-optical recording media, and FIG. 11 FIG. 2 is an explanatory diagram of recording and erasing of a magneto-optical recording medium. 10, IOA, IOB... superconducting magnetic recording medium water 12... superconducting material micro ring, 14... disk substrate, 16... superconducting film, 18... ...
...Photoresist, 22...Nonmagnetic film, 24.
...Magnetic film, 26...Recording layer, 28...
...Protective film, 30... Perpendicular magnetic moment, 36... Magnetic head, 46... Laser light emitting device, 52... Laser light source, 54 ...
...Laser light.

Claims (6)

[Claims] (1) A recording layer in which superconducting material micro-rings constituting a recording unit are arranged is provided on a substrate, and by applying an external magnetic field to each of the superconducting material micro-rings, a perpendicular magnetic moment is generated by an annular current generated in the micro-rings. A superconducting magnetic recording medium characterized by being capable of inducing. (2) The superconducting magnetic recording medium according to claim 1, characterized in that a soft magnetic material is provided at least within the superconducting material microring of the recording layer. (3) The superconducting magnetic recording medium according to claim 1, characterized in that two or more recording layers containing the superconducting microrings are formed. (4) After forming a superconducting film on a substrate by physical vapor deposition or chemical vapor deposition, a large number of micro-rings remain and are arranged, and a non-magnetic film or a magnetic film is formed around these micro-rings to form a recording layer. 1. A method of manufacturing a superconducting magnetic recording medium, comprising forming a protective film on the outer layer of the recording layer. (5) A perpendicular magnetic moment is generated by applying an external magnetic field according to a recording signal to each microring of a superconducting magnetic recording medium, which has a recording layer in which superconducting material microrings constituting a recording unit are arranged on a substrate. 1. A method for recording a superconducting magnetic recording medium, characterized in that the recorded signal is made reproducible by a magnetic head. (6) After inducing a perpendicular magnetic moment by applying a uniform external magnetic field to a superconducting magnetic recording medium having a recording layer in which superconducting material micro-rings constituting recording units are arranged on a substrate, A method for recording a superconducting magnetic recording medium, characterized in that the perpendicular magnetic moment is erased by irradiating the microring with a laser beam to destroy the superconductivity, and a digital signal is formed depending on the presence or absence of the perpendicular magnetic moment.