JPS6032261B2 - Method for manufacturing magnetic recording media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a method of manufacturing a magnetic recording medium used for a magnetic disk.

Such magnetic recording media are constructed by depositing a thin magnetic film on an AI substrate, and in order to form this thin magnetic film, a coating method in which powdered ferrite is spin-coated or a plating method is conventionally used.

By the way, in order to improve the recording density of a recording medium, the film must be made thinner to reduce the interference between the tracks on which information is recorded, and with the adoption of the contact start/stop method, the recording medium will reduce contact friction with the head during the start and stop process. In view of this, it is necessary to have a predetermined mechanical strength and further improve magnetic properties. However, with the conventional coating method described above, it is difficult to form a thin film, and with the plating method, there are problems such as lack of corrosion resistance and abrasion resistance and the need for a protective film. Therefore, in order to meet the recent demands for high-density magnetic recording media, a thin film of Q-Fe203, a non-magnetic oxide containing iron, is formed on a substrate by reactive sputtering or vapor phase growth, and this is reduced. A manufacturing method has been proposed in which a magnetic product F04 thin film is formed.

However, the current method using this method has the drawbacks that the temperature during the reduction treatment is as high as 350 oo, the reduction margin is small, and the coercive force (Hc) and squareness ratio (Br/stage) of the magnetic properties are small. There is. The present invention has been proposed to solve these drawbacks, and when forming a thin film of magnetic oxide by processing a Q-F Goods 03 thin film of non-magnetic oxide by reactive sputtering etc., reduction treatment is required. It is an object of the present invention to provide a manufacturing method that widens the temperature range and has high magnetic properties such as coercive force and squareness ratio.

Therefore, according to the present invention, Q-Fe203 contains Cr, C
u, C. Add a predetermined amount of
This method enables reduction treatment in a wide temperature range exceeding 100% and forms an Fe304 thin film having a high coercive force. In addition, the Fe304 thus formed was oxidized at a predetermined temperature range to improve its squareness and adhesion to the base.
3 to form a thin film. Next, the manufacturing method of the present invention will be explained in detail. First, Cr, C
u,C.

Film thickness lA containing a specified amount of additive elements at metal ion concentration
A Q-F Goods 03 thin film of less than m is formed by reactive sputtering,
This is then subjected to reduction treatment in a specific reducing atmosphere at a predetermined temperature range to form an Fe304 thin film. Then, the addition of Cu lowers the reduction temperature and increases the reduction margin, and the addition of Cr further widens the reduction margin, resulting in C. The coercive force increases by adding .
This will be explained in detail with reference to the characteristic curves shown in FIGS. 1 and 2. The characteristic curve in Figure 1 shows the above-mentioned reduction margin, and the electrical resistance range of about 70 to 60,000 is the region of F anchor 04, and the broken line with no additives has a reduction temperature in a very narrow range of around 300oo. Fe only at the value of
I can see that it can't happen in the 3rd quarter. On the other hand, when only Cu is added (dotted chain line), the reduction temperature at which Fe304 can be formed extends from 200qo to slightly over 300o0, and when Cu and Cr are added, the reduction temperature is as shown by the solid line. The temperature further increases to values exceeding 350 qo. In the case of Cu, this characteristic is 1 at the metal ion concentration.
Up to 5%, in the case of Cr, the metal ion concentration is 1
Possible up to 0%. In addition, the characteristic curve in Figure 2 shows the coercive force, and from this diagram it can be seen that as the amount of Co added increases, the coercive force increases proportionally, and from this point on, the optimal coercive force can be set arbitrarily. However, in reality, a metal ion concentration of 10% or less is sufficient. Furthermore, this C. Since the presence of F has almost no effect on reducibility, the 0 of F
It is very convenient to be able to handle them separately in the formation of 4. Further, the thus formed F-fin 04 thin film is further heat-treated in air or an oxidizing atmosphere in a temperature range of 150 qo to 450 qo to form a y-Fe2Q thin film.

Due to this, y-Fe203 can be used to construct magnetic recording media with magnetic oxides, just like F04, and in this oxidation treatment process, the squareness ratio is greatly improved by Cr, and the adhesion with the base is also improved. Improved. Next, the manufacturing method of the present invention -
To explain an example, 3% Cr, 2% Cu, 2%
C.

A Q-F 03 thin film was formed on an alumite-treated AI substrate by reactive sputtering in a 50% 02-50% Ar mixed gas using an F9 target containing F
4. Form a thin film. Thereafter, this Fe304 is further heat-treated in air at 30 pm to form a thin film of y-F group 03. As a result, magnetic properties with a coercive force of 700Q and a squareness ratio of 0.8 were obtained. As explained above, according to the manufacturing method of the present invention, a non-magnetic oxide film can be reduced in an atmosphere with a wide temperature range, making it possible to easily obtain a thin magnetic oxide film and further improving magnetic properties. As a result, higher density of magnetic recording media can be achieved.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the state of the reduction margin according to the conventional method and the present invention, and FIG. 2 is a characteristic diagram showing the state of the coercive force according to the present invention. Q-F203...Nonmagnetic oxide, Fe304,
F203...Magnetic oxide. *2 books 1 illustration

Claims (1)

[Claims] 1. A method characterized by forming an α-Fe_2O_3 thin film of a non-magnetic oxide to which Cr, Cu, and Co are added on a substrate, and then subjecting it to a reduction treatment to obtain a Fe_3O_4 thin film of a magnetic oxide. A method for manufacturing a magnetic recording medium. 2 Form a non-magnetic oxide α-Fe_2O_3 thin film to which Cr, Cu, and Co are added on the substrate, then reduce it to form a magnetic oxide Fe_3O_4 thin film, and further heat-treat and oxidize it to make it magnetic. Oxide α-Fe_
A method for producing a magnetic recording medium, characterized by obtaining a 2O_3 thin film.