JPH04324101A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve S/N by performing the necessary control of the imparting direction of the axis of easy magnetization of the magnetically soft backing layer of the magnetic recording medium of two-layer film structure and the direction of the width of the return yoke for the width of the main magnetic pole of the magnetic head. CONSTITUTION:A perpendicular magnetic disk 31 of the magnetic recording medium has a magnetically soft backing layer 33 and a perpendicular magnetic disk layer 34, etc. The axis of easy magnetization of this layer 33 is defined as the peripheral direction of the disk 31 and the arrangement control is performed for a return yoke 142 opposed to a main magnetic pole 45 of a magnetic head 41 to have the size of width so that the lines connecting with each side end part of the main magnetic pole 45 and each side end part corresponding to the yoke is capable of having at least 60-degree opening. Thus, S/N is improved at the time of reproduction without being crossed by the magnetic domain of the layer 33 since the layer is formed in the recording track direction, without the phenomenon that the magnetic domain cross the head 41 and without the deterioration of the recording and reproducing efficiency.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perpendicular magnetic recording type magnetic disk device, and more particularly to a magnetic disk device with excellent perpendicular recording and reproducing characteristics.

[0002] In recent years, magnetic disk devices have been required to have large capacity and high density recording, and so-called high permeability soft magnetic underlayers and so-called high magnetic permeability soft magnetic backing layers have been developed to enable higher density recording than conventional horizontal magnetic recording systems. 2. Description of the Related Art A device structure that combines a magnetic recording medium with a two-layer structure in which perpendicularly magnetized films are laminated and a main pole excitation type magnetic head that records and reproduces information on the magnetic recording medium is being put into practical use.

[0003] In a magnetic disk device having such a configuration,
Along with higher density recording, it is necessary to have high recording and reproducing efficiency and high S/N characteristics.

0004

2. Description of the Related Art As shown in FIG. 3, a conventional perpendicular magnetic recording type magnetic disk device uses Ni-F on a non-magnetic substrate 2 made of, for example, aluminum with NiP surface treatment.
A soft magnetic backing layer 3 with high magnetic permeability made of e.g. Co-C
A magnetic recording medium having a two-layer film structure in which a perpendicular magnetization film 4 having magnetic anisotropy in the perpendicular direction is laminated, consisting of a perpendicular magnetic disk 1 and a magnetic flux return path for the slider and main pole 14. With respect to the return yoke 12, a main magnetic pole 14 made of a Ni-Fe alloy or the like is exposed at its tip to the medium facing surface via an excitation coil 13 covered with an interlayer insulating film made of a hardening resin material or the like. It has a configuration in which a main pole excitation type magnetic head 11 is arranged such that its rear end is magnetically connected to a return yoke 12.

[0005]The soft magnetic backing layer 3 having a high magnetic permeability in the perpendicular magnetic disk 1 having a double-layer film structure on which information is recorded and reproduced by the magnetic head 11 has a high magnetic permeability during recording and reproduction, as shown by arrows in the figure. By making it a part of the magnetic flux return path between the main magnetic pole 14 of the head 11 and the return yoke 12, high-density perpendicular magnetic recording and reproduction can be performed on the perpendicular magnetization film 4 of the perpendicular magnetic disk 1. There is.

Further, in such a device configuration, the main pole 14 and the return yoke 12 of the main pole excitation type magnetic head 11 are arranged in the recording track direction (circumferential direction of the disk) with respect to the perpendicular magnetic disk 1. Because of the arrangement, the magnetic flux from the main pole 14 is efficiently returned to the return yoke 12 via the soft magnetic underlayer 3 of the perpendicular magnetic disk 1 having a double-layer structure, as shown by the chain line. The easy axis of magnetization of the soft magnetic underlayer 3 is provided in the radial direction of the perpendicular magnetic disk 1 to increase the magnetic permeability in the recording track direction (circumferential direction of the disk).

[0007]

[Problems to be Solved by the Invention] In the conventional magnetic disk device as described above, the magnetic permeability of the perpendicular magnetic disk 1 having a double-layer film structure in the recording track direction (circumferential direction of the disk) is high, and the magnetic permeability is high in the radial direction. In the soft magnetic backing layer 3 with the axis of easy magnetization at Since it intersects with the recording track running with respect to the magnetic head 11, it becomes a noise source during recording and reproduction, and the S/N
There was a drawback that the characteristics deteriorated.

In view of the above-mentioned conventional drawbacks, the present invention has been developed based on the direction in which the axis of easy magnetization of the soft magnetic underlayer in a magnetic recording medium with a two-layer film structure is provided and the width of the main pole of a main pole excitation type magnetic head. To provide a new magnetic disk device in which the width of a return yoke facing the main magnetic pole is appropriately controlled to improve S/N characteristics during recording and reproduction without reducing recording and reproduction efficiency. This is the purpose.

[0009]

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the present invention provides a magnetic recording medium having a two-layer structure in which a soft magnetic underlayer and a perpendicularly magnetized film are laminated on a non-magnetic substrate, and a magnetic recording medium on a medium facing surface. A magnetic disk device comprising a main magnetic pole excitation type magnetic head having a main magnetic pole whose tip end is exposed and a return yoke forming a return path for the main magnetic pole, the magnetic disk device comprising: The axis of easy magnetization of the underlayer is provided in the circumferential direction of the magnetic recording medium, and a return yoke facing the main magnetic pole of the magnetic head is arranged between each side end of the main magnetic pole and each corresponding one of the return yokes. The width dimension is such that the line connecting the side ends has an opening angle of at least 60 degrees.

0010

[Function] In the magnetic disk device of the present invention, the axis of easy magnetization of the soft magnetic underlayer in the magnetic recording medium of the two-layer film structure is given in the circumferential direction (recording track direction) of the magnetic recording medium, and the magnetic In a main pole excitation type magnetic head that records and reproduces information in combination with a recording medium, the width of the return yoke that faces the main pole is defined as the width of each side end of the main pole and the corresponding side end of the return yoke. By arranging the width dimensions such that the lines connecting the two have an opening angle of at least 60 degrees, the magnetic domains of the soft magnetic underlayer in the magnetic recording medium during recording and reproduction are formed in the direction of the recording track. Since the phenomenon in which the magnetic domain intersects with the main pole excitation type magnetic head is eliminated, noise generation is reduced.

In addition, the recording track direction of the soft magnetic underlayer in the magnetic recording medium is the easy axis of magnetization in this case, but the width of the return yoke facing the main pole in the main pole excitation type magnetic head is By making the width dimension larger than the width of the magnetic pole as described above (actually, the width dimension is at least five times the width of the main magnetic pole), the soft magnetism of the magnetic recording medium corresponding to the area between the main magnetic pole and the return yoke can be improved. The contribution rate of the magnetic path with high magnetic permeability in the radial direction in the magnetic flux return region of the underlayer increases.

That is, although the magnetic permeability in this magnetic flux return region decreases due to deviation from the direction of the hard axis of magnetization, at least 30% of the magnetic permeability in the direction of the hard axis of magnetization is ensured. As a result, S/N
A magnetic disk device with high characteristics can be realized.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view schematically showing an embodiment of a magnetic disk device of the present invention.

In the figure, reference numeral 31 denotes a magnetic recording medium with a two-layer film structure, that is, a perpendicular magnetic disk. For example, the surface of a non-magnetic substrate 32 made of aluminum with NiP surface treatment is textured in the circumferential direction ( After forming fine scratch-like grooves in the circumferential direction (recording track direction), a Ni-Fe film with a thickness of 1 μm is formed on the surface by electroplating.
A soft magnetic backing layer 33 with high magnetic permeability having an easy axis of magnetization is formed by sputtering to form a Co-coat layer with a thickness of 0.15 μm.
A perpendicularly magnetized film 34 made of a Cr film and having magnetic anisotropy in the perpendicular direction is laminated, and its surface is further coated with a protective film (not shown) made of carbon or the like having a thickness of 0.02 μm.

Reference numeral 41 denotes a main pole excitation type magnetic head, which is connected to a return yoke 42 made of a ferrite material such as Mn-Zn or Ni-Zn, which constitutes a return path for the magnetic flux to the slider and the main pole 45. A main magnetic pole 45 made of a Ni-Fe alloy or the like is exposed at its tip to the medium facing surface through an excitation coil 44 covered with an interlayer insulating film 43 made of a hardening resin material or the like, and its rear end is exposed to the return surface. It is arranged to be magnetically connected to the yoke 42.

Furthermore, such a main pole excitation type magnetic head 4
Return yoke 4 facing the main magnetic pole 45 in 1
The width (Rw) of No. 2 is such that the line connecting each side end of the main pole 45 and the corresponding side end of the return yoke 42 has an opening angle of at least 60 degrees, as shown in FIG. 2 when viewed from the disk side. (
2θ). For example, as a practical example, the width (Tw) of the main magnetic pole 45 is 10 μm, and the distance (D) between the main magnetic pole 45 and the return yoke 42 is 100 μm (3 of the width of the main magnetic pole 45).
In this case, the width (Rw) of the return yoke 42 facing the main magnetic pole 45 is set to 200 μm (5 times or more the width (Tw) of the main magnetic pole 45).

Such a main pole excitation type magnetic head 4
1 and a perpendicular magnetic disk 31 having a two-layer film structure and having a soft magnetic backing layer 33 with high magnetic permeability and having an axis of easy magnetization in the circumferential direction (recording track direction), recording and reproducing can be performed. Since the magnetic domains of the soft magnetic underlayer in the perpendicular magnetic disk 31 are formed in the direction of the recording track, the magnetic domains do not intersect with the main pole excitation type magnetic head 41, thereby reducing noise caused by the direction of the magnetic domains. occurrence is significantly reduced. Further, the magnetic head 41
By making the width (Rw) of the return yoke 42 facing the main magnetic pole 45 larger than the width (Tw) of the main magnetic pole 45 as described above, the width can be adjusted between the main magnetic pole 45 and the return yoke 42. Since the contribution rate of the magnetic path with high magnetic permeability in the radial direction in the magnetic flux return region of the soft magnetic underlayer 33 of the perpendicular magnetic disk 31 increases, there is no fear that the recording and reproducing efficiency will decrease.

In the above embodiment, as a method for imparting the axis of easy magnetization of the soft magnetic underlayer 33 in the perpendicular magnetic disk 31 in the circumferential direction (recording track direction) of the perpendicular magnetic disk 31, the surface of the nonmagnetic substrate 32 is In the previous section, we explained a method for imparting shape magnetic anisotropy using fine scratch-like grooves formed in the circumferential direction (recording track direction) by texture processing, etc., but in addition to examples of such methods, for example, induced magnetic anisotropy A method of imparting properties or magnetocrystalline anisotropy can also be used.

Incidentally, the combination structure of the magnetic head 41 of this embodiment and the perpendicular magnetic disk 31, the combination structure of the magnetic head 41 of this embodiment and the conventional perpendicular magnetic disk, and the perpendicular magnetic disk of this embodiment Table 1 shows the results of measuring and comparing various characteristics of the combination configuration with a conventional magnetic head.

[0020]

[Table 1]

As is clear from Table 1, the combination configuration of the magnetic head 41 and perpendicular magnetic disk 31 of this embodiment is different from the combination configuration of the magnetic head 41 of this embodiment and the conventional perpendicular magnetic disk. There is almost no difference in terms of reproduction output, and there is no change in recording and reproduction efficiency, but since the generation of noise during recording and reproduction is significantly reduced, the S/N characteristic is improved and the recording density is improved.

Furthermore, the combination configuration of the perpendicular magnetic disk of this embodiment and the conventional magnetic head has a reproduction output approximately 70% higher than that of the combination configuration of the magnetic head 41 and the perpendicular magnetic disk 31 of this embodiment. It is declining.

[0023]

As is clear from the above description, according to the magnetic disk device according to the present invention, a double-layer film in which the direction of easy magnetization axis of the soft magnetic underlayer with high magnetic permeability is controlled in the direction of the recording track. By combining a magnetic recording medium with a main magnetic pole structure and a main magnetic pole excitation type magnetic head in which the width of the return yoke facing the main magnetic pole is appropriately controlled relative to the width of the main magnetic pole, recording and reproducing efficiency can be improved. This makes it possible to improve the S/N characteristics during recording and reproduction without reducing the S/N characteristics, and has the excellent effect of improving the recording density.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing an embodiment of a magnetic disk device of the present invention.

FIG. 2 is a plan view for explaining the configuration of an embodiment of the magnetic head of the present invention.

FIG. 3 is a perspective view schematically shown to explain a conventional magnetic disk device.

[Explanation of symbols]

31 Vertical magnetic disk 32 Non-magnetic substrate 33 Soft magnetic backing layer 34 Perpendicular magnetization film 41 Magnetic head 42 Return yoke 43 Interlayer insulation layer 44 Excitation coil 45 Main magnetic pole

Claims (1)

[Claims] Claim 1: A magnetic recording medium (31) having a two-layer film structure in which a soft magnetic underlayer (33) and a perpendicular magnetization film (34) are laminated on a non-magnetic substrate (32), and a tip end of each on the medium facing surface. This is a magnetic disk device comprising a main pole excitation type magnetic head (41) equipped with a main pole (45) having an exposed main pole (45) and a return yoke (42) forming a return path for the main pole (45). Then, the magnetic recording medium (3
The easy axis of magnetization of the soft magnetic underlayer (33) in 1) is provided in the recording track direction of the magnetic recording medium (31), and the main magnetic pole (
The return yoke (42) facing the main magnetic pole (45) is arranged such that a line connecting each side end of the main magnetic pole (45) and each corresponding side end of the return yoke (42) has an opening angle of at least 60 degrees. A magnetic disk device characterized in that the magnetic disk device is arranged with a width dimension.