JPS60125919A - Vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve recording and reproducing characteristics by forming ''Permalloy'' films into multi-layered structure. CONSTITUTION:''Permalloy'' films and vertically magnetized Co-Cr film 2 are provided on a nonmagnetic base plate. The ''Permalloy'' film of a two-layered medium is made into the two-layered structure having two layers of ''Permalloy'' layers 6 separated by a nonmagnetic layer 7 and ''Permalloy'' films 5 are made into the 4-layered structure having 4-layers of ''Permalloy'' layers 6' divided and parted by respective nonmagnetic layers 7'. If the ''Permalloy'' film made into multi-layered structure, the reproduced output increases as compared to the case in which the ''Permalloy'' film consists of the single-layered structure. The thicknesses of the layers 6, 6' are required to be made <=2,000Angstrom in terms of initial magnetic permeability and are further made <=1,200Angstrom in view of stability. The nonmagnetic layer thickness is required to be made 10-500Angstrom . The Ti film is most suitable as the nonmagnetic layer.

Description

[Detailed description of the invention] Industrial applications This invention relates to a perpendicular magnetic recording medium.

Conventional Structure and Problems There is a perpendicular magnetic recording system as a magnetic recording system with excellent short wavelength recording characteristics. This method requires a perpendicular magnetic recording medium whose easy axis is approximately perpendicular to the film surface of the medium. When a signal is recorded on such a medium, the residual magnetization is oriented in a direction substantially perpendicular to the film surface of the medium, and therefore, the shorter the wavelength of the signal, the smaller the demagnetizing field within the medium, resulting in excellent reproduction output. A Co-Cr perpendicular magnetic recording medium, which is called a single-layer film medium, is a perpendicularly magnetized film mainly composed of Co-Cr, which is deposited on a substrate made of a non-magnetic material by a sputtering method or a vacuum evaporation method (such as an ion-blating method). (including the method of ionizing and ionizing a part of the volcanic atoms). In a single-layer film medium having such a structure, a permalloy film 3 is provided between a substrate l made of non-magnetic paulownia material and a Co-Cr perpendicularly magnetized film 2 as shown in FIG. So-called 2
It is known that recording efficiency and reproduction output can be improved by using a structure called a layered film medium. In particular, when recording and reproducing using the known auxiliary pole excitation type vertical helenoid, the recording efficiency is improved by about 20 dB and the reproduction output is improved by about 20 dB.

As mentioned above, excellent recording and reproducing characteristics can be obtained by using a dual-layer film medium, but considering the increasing density and miniaturization of magnetic recording and reproducing devices, the characteristics are still insufficient.
Saws that require even better properties.

OBJECT OF THE INVENTION An object of the present invention is to provide a perpendicular magnetic travel medium with exceptionally excellent recording and reproducing characteristics.

Structure of the Invention The perpendicular magnetic recording medium of the present invention comprises a non-magnetic substrate, a permalloy film formed on the non-magnetic substrate with at least one non-magnetic layer disposed within the film, and a permalloy film directly on the permalloy film. Alternatively, a Co--Cr perpendicular magnetization film formed via a nonmagnetic layer is provided.

Description of examples The present invention will be explained in detail using FIGS. 2 to 5.

In the conventional two-layer film medium, the permalloy film 3 has a single-layer structure as shown in FIG. It has a multilayer structure as shown in Figure 3. That is, the permalloy film 4 shown in FIG.
The permalloy film 5 in Fig. 3 has a two-layer structure with
In this method, a non-magnetic layer 7' is provided in the film, and each magnetic layer 7' is
It has a four-layer structure with four permalloy layers 6 separated by '.

A permalloy film is made into a multilayer structure to create a two-layer film medium,
When recording and reproducing characteristics are measured, the permalloy film has a tri-layer structure.
I was bitten. This will be explained below.

FIG. 4 shows the reproduction output when the total film thickness and structure of the permanent 1'' film are changed in the 21MIIQ medium.

Note that the film thickness of the Co-Cr:g: direct magnetization layer is constant at 1500, and the non-magnetic layer in the permalloy film is 89710.
0 people's i" i l was vague. In addition, signal recording and reproduction was performed using a drum-shaped vertical head (IJJ), and the recording density was 5 (l K F l) l' l. ,
5 (l K I' RP 1 means 1 in 50
This is a recording state of a distal signal with 000 magnetization reversals. Curves 8.9 and 10 in Fig. 4 are the total film thickness of the permalloy film when the structure of the permalloy film is 11.1 structure, 21 structure, and 4 layer structure, respectively. ,
The relationship with the playback output is small (.From this figure, the perm l'
If the total film thickness is constant, perm 1! It can be seen that the I9 has a multi-layer structure, and the greater the number of layers, the higher the reproduction output. The reason for this is the size of the first transparent ωIJ of the perm gland.
It is thought that this is because the initial magnetic permeability of the film increases as the I thickness becomes thinner.

FIG. 5 shows the relationship between film thickness and initial magnetic permeability when a permalloy film is formed by vacuum evaporation on a substrate made of a heat-resistant polymeric material. In a two-layer film medium, the permalloy film acts as part of the heno during recording and reproduction. As a result, the initial magnetic permeability of the permanent coil film must be at least 1000. From Figure 5, perm 1 with an initial permeability of 1000 or more! It can be seen that in order to obtain a good film, the film thickness needs to be 2000 Å or less. However, in the vicinity of 2000 people, when the film thickness changes, the initial permeability also changes, resulting in poor stability. permalloy membrane
When y is set to 1200 Å or less, the initial magnetic permeability is approximately 2500
becomes constant and stability increases. It has been experimentally confirmed that the initial permeability θ of such a permalloy film does not change even if multiple layers are stacked with a non-magnetic layer of 10 Å or more in between.6 Therefore, from the viewpoint of initial permeability , the permalloy layer (in the case of Figures 2 and 3, the layer thickness of 6.61 is 200
The thickness needs to be 0 Å or less, and from the viewpoint of G stability, it is preferably 1200 Å or less.

I went to Japan. When stacking multiple permalloy layers on J, ·), Permal +: +- (The non-O-resilient layer thickness between the layers must be on IOAO) J! When it becomes less than 10 Å, permalloy) τ); for the phases I+' and I'l increases rapidly,
The initial permeability decreases. ; Tominmu this non-theta state soil 1ml'
If there are more than 1 or 500 people, 2 h□i JIG: Medium Q Koshino, 2 Case Notes 3 Me 41:,! 1. i-ness deteriorates rapidly. Although the cause of this is not clear, it is thought to be due to the loss of space between the conventional cursor and the medium.

2) In the N film body, the C-axis of the Co-C: r perpendicularly magnetized film or hcI- structure must be oriented in the perpendicular direction of blood removal, but considering this orientation, the perm 1- 14
It has become clear that the most suitable non-magnetic layer for separating the layers is '1'1'. Zumuwara, 1”
When using i llshi as non(='A 'l!h 1m, c.

The half-value width Δ05 (, of the LJ7 King curve for the (002) plane of the -Cr arm is less than 10゛, and the orientation is excellent -C
Iroga uses AI, Cu, and SiO as the nonmagnetic layer.

5i02. When using Δ1203 etc., half width Δ05o
has become more than 20 layers.

Next, a more specific example will be explained.

First concrete example A first specific example will be described using FIG. 6.

In the figure, 11 is a film substrate made of heat-resistant polymer paulownia material with a film thickness of 50 μnl, and 12 is a Co film with a film thickness of 2000 μnl.
- Cr1q direct magnetization film, 13 is a permalloy film, permalloy layer 14 of 200 people has a film thickness of 1゛1 of 80 people.
It has a 3M structure in which three layers are stacked with a membrane 15 in between. A double-layer film medium with such a structure is used with an auxiliary magnetic pole excitation type perpendicular head.
When a signal of KF Rl)1 is recorded and reproduced, the reproduction output is 30 dr3 higher than that of the conventional Co-containing iron oxide coated medium. I got fucked. Furthermore, a 9 dB higher reproduction output was obtained for the 2j renal membrane medium, which had the same structure as in FIG. 6 except that the permalloy membrane had a single-layer structure and the hip Ig was 3600.

Second specific example A second specific example will be described using FIG. 7.

In this case, the permalloy film 13 and the Go-Cr perpendicular magnetization film 1
The structure is the same as that shown in FIG. 6, except that a Ti film 16 with a thickness of 300 mm is present between the Ti film 2 and the Ti film 16.

Kogo゛(,'+' r II* l 6 is Co-(:,
This is provided to improve the orientation of the r-perpendicularly magnetized film 12. A 21M crotch medium with such a structure has an auxiliary θ ripolar excitation type perpendicular to 71' at 100 K + ·' 1. ! I) When recording and reproducing the I signal, a 1.1 raw output was obtained, which was 32 dB higher than the conventional CO-containing white iron oxide coated medium.

Third specific example A third specific example will be described using FIG. 8.

In this case, there is a film thickness of 300 between the permanent coil film 13 and the film substrate 11 made of a heat-resistant polymer material.
It has the same 411i construction as in FIG. 6 except for the presence of the 1 film 17. Here, the 'I' i film 17 is similar to the second specific example (:
This is provided to revise 1t. 21i with this kind of structure
9 types of auxiliary magnetic pole excitation perpendicular to the grinding medium] 00
When the KFRI) I signal was recorded and reproduced, a reproduction output 34 dB higher than that of the conventional Co-containing iron oxide coated medium was obtained.

Effects of the Invention According to the present invention, there is an effect that extremely excellent recording and reproducing characteristics can be obtained.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the structure of a conventional two-layer film medium, Figs. 2 and 3 are sectional views showing an embodiment of a 2NN film body according to the present invention, and Fig. 4 shows the total film pressure of the permalloy film. FIG. 5 is a characteristic diagram of the relationship between the permalloy film thickness and initial magnetic permeability, and FIGS. FIG. 2 is a sectional view of a two-layer film medium that is a second specific example. 1.11-Substrate, 2.12-Co-Cr perpendicular magnetization film, 4
．． 5. 13 Permalloy film, 6, 14 Permalloy layer, 7 Non-magnetic layer (・, − Agent Patent Attorney Official I...1", 'JTB'l. Figure 1 Figure 2 Figure 3 Figure n (4 Figure 0 1000 2000 3000 -1\゛-70 Iryo no Membrane/! (in) Figure 5

Claims (1)

[Claims] (11) A permanent l formed on a non-magnetic W plate and the non-magnetic Ik plate with at least one non-magnetic layer disposed within the film:
(1) A vertical magnetic recording medium with a Co-Cr perpendicular magnetization film formed directly or through a nonmagnetic layer. (2) A nonmagnetic layer in the permalloy film. The perpendicular magnetic recording medium according to claim (1), wherein each permalloy layer separated by a layer has a thickness of 2000 F or more. (3) Each permalloy layer separated by a nonmagnetic layer in the permalloy film The perpendicular magnetic recording medium according to claim (1), wherein the layer j7 has a thickness of 1.200 Å or less. (4) The perpendicular magnetic recording medium according to claim (1), wherein the nonmagnetic layer in the permalloy film is a Ti film. ) The perpendicular magnetic recording medium according to item (2) or item (3). (5) The thickness of the nonmagnetic layer in the permalloy film is 10 or more.
A perpendicular magnetic recording medium according to claim (1), (2), (3) or (4) within the range of 500 people.