JPH0552567B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing an iron oxide magnetic thin film used as a recording medium in a magnetic disk device or the like. (Prior art and its problems) Improvement in recording density in magnetic recording devices is a constant trend in the field, and in order to achieve this, it is essential to make magnetic recording bodies thinner and thinner. Therefore, continuous thin film media that can be easily made thin, particularly iron oxide magnetic thin films, are attracting attention as high-performance magnetic recording bodies. The reason is (1) the residual magnetic flux density is small;
(2) It has high mechanical strength and chemical stability, and does not require the protective film required for thin metal films.As a result, (3) the space between the magnetic head and the medium is smaller, resulting in higher density. The reason is that it is suitable for lowering prices. Various methods have been proposed for forming these iron oxide magnetic thin films, but as seen in JP-A-58-4914, Fe ₃ O ₄ sintered bodies are targeted and Fe ₃ O ₄ is directly formed as the main component by sputtering. A method of forming an iron oxide magnetic thin film containing γ-Fe ₂ O _{3 as a main component and thermally oxidizing it to form an iron oxide magnetic thin film containing γ-Fe 2 O 3} as a main component is simple and suitable for mass production. The substrate used here is generally
A substrate with an anodic oxide film coated on an Al alloy is used. However, depending on the thermal oxidation treatment temperature in the γ-Fe ₂ O ₃ conversion process of the magnetic film, cracks may occur due to the difference in thermal expansion between the Al alloy and the oxide coating layer.
It is desirable that the temperature of the γ-Fe ₂ O ₃ conversion treatment be as low as possible because problems such as a decrease in S/N of the recording medium occur due to changes in the substrate due to heat treatment. (Object of the Invention) The object of the present invention is to eliminate such conventional drawbacks, reduce the thermal oxidation treatment temperature, and provide a high-performance magnetic recording medium. (Structure of the invention) Targeting ferrite mainly composed of magnetite or magnetite containing additives,
After forming a continuous thin film of iron oxide mainly composed of magnetite or magnetite containing additives on a substrate by sputtering, it is thermally oxidized to form γ-Fe ₂ O _3.
Or, in the production method of forming a continuous iron oxide thin film mainly composed of γ-Fe ₂ O ₃ and Fe ₃ O ₄ or containing additives, the sputtering pressure during formation of the iron oxide continuous thin film is changed from high sputtering pressure to high sputtering pressure. A method for manufacturing a magnetic memory body is obtained, which is characterized in that the sputtering pressure is changed stepwise or continuously to a low sputtering pressure. (Detailed Description of Configuration) The present invention solves the problems of the prior art by taking the above-described method. That is, as the sputtering pressure during formation of a continuous iron oxide thin film is increased, a film with a higher degree of oxidation can be obtained, and when this is thermally oxidized, γ-Fe ₂ O ₃ can be obtained at a lower temperature as the film has a higher degree of oxidation. Therefore, by providing a film having a composition with a high degree of oxidation on a lower layer where oxidation is slow during film formation as in the present method, oxidation of the entire film can be easily promoted. (Example) Examples of the present invention will be described below. First, the sputtering pressure during the formation of a continuous iron oxide thin film
P _Ar from high sputtering pressure to 1×10 ^-2 Torr, 4×
10 ^-3 Torr, 2×10 ^-3 Torr and low sputter pressure3
Sample 1, 1×10 ^-2 formed by changing the step pressure
Sample 2 was formed by continuously changing the pressure from Torr to 2 × 10 ^-3 Torr, and then as a comparative example, the pressure was changed to 2 × 10 -3 Torr.
Sample 3 was prepared at a constant 10 ^-3 Torr. 2wt%Co, 3wt%Cu for sputter target
The thickness of the continuous iron oxide thin film was 0.18 μm using magnetite containing . Samples 1 to 3 were thermally oxidized in the atmosphere at 260°C (at 260°C and 300°C or higher for sample 3) for 1 hour. The table shows the electrical resistance of each thin film after thermal oxidation.

[Table] (Effects of the Invention) As described above, according to the present invention, the thermal oxidation temperature can be significantly lowered than in the past, and crack generation and S/N reduction can be prevented.

Claims (1)

[Claims] 1 Targeting ferrite mainly composed of magnetite or magnetite containing additives, a continuous thin film of iron oxide mainly composed of magnetite or magnetite containing additives is formed on the substrate by sputtering with argon gas, and then thermally oxidized. γ-Fe ₂ O ₃ or γ-Fe ₂ O ₃ and Fe ₃
In a manufacturing method for forming a continuous thin film of iron oxide mainly composed of O ₄ or containing additives, the sputtering pressure during formation of the continuous thin film of iron oxide is changed stepwise or continuously from high pressure to low pressure. A method for manufacturing a magnetic memory body, characterized in that: