JPS629517A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To prevent noise and to improve S/N by forming a magnetic film of data tracks of a magnetic recording medium in such a manner that the vertical magnetic anisotropy of said film is layer than the vertical magnetic anisotropy of the guard band tracks between the data tracks. CONSTITUTION:After a thin vertical magnetic recording film 3 is formed on a substrate 4 by using a sputtering method, etc., the substrate 4 is rotated under the irradiation of laser light 5 thereto to heat the thin vertical magnetic recording film 3 in the part of the data tracks 1 consisting of the concentrical circles on the substrate 4. The vertical magnetic anisotropy of the film 3 in the part of the data tracks 1 heated by the laser light 5 is increased and the coercive force thereof is increased as well. As a result, the recording and reproducing characteristics in the data tracks 1 permit the higher density recording than on the guard band tracks 2 between the data tracks 1 and the high output is obtd. The output of the record in the guard band tracks generated by the deviation of tracking is made substantially smaller than the output from the data tracks 1 in the high-density recording region and the crosstalk, etc. by the deviation of the adjacent tracks are suppressed.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a magnetic recording medium that magnetically records data, and particularly to a magnetic recording medium that records data by perpendicular magnetic recording. The present invention relates to a magnetic recording medium with improved off-track characteristics related to tracking accuracy, which is a problem with density, and a method for manufacturing the same.

(Prior art and its problems) Improving the recording density of magnetic recording devices is a constant trend in the field. Conventionally, magnetic recording bodies used in magnetic recording devices generally perform recording and reproduction by KM in the longitudinal direction of the recording medium.
As the density increases, there is a limit to the recording density due to the influence of the demagnetizing field.The perpendicular magnetic recording method, which magnetizes perpendicularly to the medium surface of the recording medium, which makes it possible to increase the density, has been proposed, which has reduced the recording density to 1% of the conventional recording density. Achieved a value of more than an order of magnitude.

As a perpendicular magnetic recording medium used in computers.

There is a Co alloy thin film typified by CoCrK formed by sputtering or vapor deposition. In this way, in the perpendicular magnetic recording method, it is possible to significantly improve the linear density in the recording track direction on the recording medium surface by giving the medium perpendicular magnetic anisotropy. In order to improve the density, it is necessary to increase the track density by more than an order of magnitude. With increasing track density.

If sufficient tracking accuracy is not obtained, noise may be generated due to unerased data, and the S/N ratio (S: signal, N: noise) may decrease due to crosstalk noise from recorded bits due to tracking deviation of adjacent tracks. It arises.

(Object of the Invention) An object of the present invention is to solve the above-mentioned problems and improve the perpendicular magnetic anisotropy of a magnetic film of a data track of a magnetic film having magnetic anisotropy perpendicular to the film surface formed on a substrate. Our goal is to provide a magnetic recording medium in which noise is prevented and the S/N ratio is improved by making the coercive force larger than the perpendicular magnetic anisotropy and coercive force of the guard band between data tracks, and a method for manufacturing the same. .

(Structure of the Invention) The present invention provides a magnetic recording medium in which a magnetic film having magnetic anisotropy perpendicular to the film surface is formed on a substrate, and the present invention provides perpendicular magnetic anisotropy and retention of data track portions of the magnetic film. A magnetic force is applied to the data tracker of the magnetic film.

The perpendicular magnetic anisotropy and coercive force of the guard band track portion between the edges are larger than that of the guard band track.

The method for producing a magnetic recording body of the present invention includes forming a magnetic film having magnetic anisotropy perpendicularly to the film surface on a substrate, and then heating the data track portion on the monumental film by irradiating it with light. It is characterized by

(Example) Next, the present invention will be explained using the drawings.

FIGS. 1 and 2 are a perspective view showing a partially cutaway magnetic disk according to an embodiment of the present invention and a perspective view showing a manufacturing method, respectively. After forming a perpendicular magnetic recording thin film 3 on a substrate 4 using a sputtering method or the like, the substrate 4 is rotated while being irradiated with a laser beam 5 as shown in FIG. The perpendicular magnetic recording thin film 3 is heated. Note that the laser beam 5 is irradiated from a laser irradiation device fiii6 through a lens 7.

The perpendicular magnetic anisotropy of the data track 1 portion of the perpendicular magnetic recording thin film 3 heated by the laser beam 5 increases, and the coercive force also increases. As a result, the recording/reproducing characteristics in the data track 1 enable higher density recording and higher output than on the guard band track 2 between the data tracks 1, and in the high recording density area, the guard band whose magnetization shifts due to tracking bias. The recording output to track 2 can be made sufficiently smaller than the output from data track 1, and crosstalk due to tracking deviation in adjacent tracks can also be suppressed, so that a signal with a large S/N ratio can be obtained.

In the embodiment shown in FIG. 1, an aluminum alloy substrate to be anodized is used as the base 4, and a substrate is coated on the base 4.

A perpendicular magnetic recorder [3] consisting of a CoCr thin film with a thickness of 0.3 μm was formed by sputtering using a CoCr alloy target using the method. The perpendicular magnetic anisotropy field Hk of this CoCr thin film is 2. QKOe, coercive force HCL is 3
000e, and the saturation magnetization Ms was 300 emu/cc.

In the embodiment of the manufacturing method shown in FIG. 2, a CO2 laser was used as the laser irradiation device 6 to irradiate and heat the data track 1. The perpendicular magnetic anisotropy field Hk of the sample treated under the same conditions was 5.0 KOe and the coercive force HCL was 8000e.
Tona-1) In order to confirm the 7'C0 effect, data track 1 of the embodiment shown in Fig. 1 is replaced with guard band track 2.
The recording density characteristics of the ring type magnetism with a gap length of 0.25 μm were changed to a spacing of 0.05 using Mn-Zn.
Measured in μm. The results are shown in Figure 3 (curve 10 is data track 19 curve 11 is gartband track 2
). On data track 1, the solitary wave output is 172, and the recording density DI$6 is 140 KPR.
, PI Tearari, On the other hand, the recording density Dse of the solitary wave output of 172 on Hunttora and Ri2 is 60.
It was KFRPI. Additionally, the power was approximately 1.7 times greater on data track 1 than on guard band track 2. Therefore, approximately 60KFRP for data track l
At a recording density of I or more, the reproduction output from the guard band track 2 was sufficiently smaller than the output from the data track 1, and good off-traffic characteristics could be obtained.

In the embodiment shown in FIG. 1, a CoCr single-layer film is shown as an example, but the present invention may also be applied to a two-layer film using NiFe or the like as a base thin film of a CoCr thin film.

(Effects of the Invention) As described above, the present invention makes the perpendicular magnetic anisotropy of the magnetic film of the data track in a magnetic recording medium thicker than the superimposed magnetic anisotropy of the guard band track between the data tracks. Therefore, even if data is recorded in the guard band due to the tracking deviation at the used recording density of the data track, the reproduction output is sufficiently small, and crosstalk from adjacent tracks can also be suppressed.

Furthermore, by defining data tracks on the magnetic recording medium side, the present invention can improve tracking accuracy and greatly improve servo merge even when sector servo or the like is used.

[Brief explanation of the drawing]

1 and 2 are a perspective view showing a part of an embodiment of the present invention and a perspective view showing a manufacturing method thereof, respectively, and FIG. 3 shows a data track 1 and a guard band track of the embodiment shown in FIG. 1. 2 is a graph showing the recording characteristics of No. 2. 1... Data track, 2... Gart band, 3... Perpendicular magnetic recording thin film, 4...
... Base, 5 ... Laser light, 6 ... Laser irradiation device, 7 ... Lens. ! I; Data and rack 42-j), #, fzl/-the°°-χ. Otsu; L-“su°°′-teruha-r sending Eλ [7:
Ren person Figure 2

Claims (2)

[Claims] (1) In a magnetic recording body in which a magnetic film having magnetic anisotropy perpendicular to the film surface is formed on a substrate, the perpendicular magnetic anisotropy and coercive force of the data track portion of the magnetic film are A magnetic recording body characterized in that the perpendicular magnetic anisotropy and coercive force are larger than the guard band track portion between the data tracks. (2) A magnetic recording body characterized by forming a magnetic film having magnetic anisotropy perpendicular to the film surface on a substrate, and then heating the data track portion on the magnetic film by irradiating it with light. Production method.