JPS6029940A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To accelerate adequately oxidation so that gamma-Fe2O3 is uniformly formed by subjecting repeatedly plural times the same base material to a film- forming stage and oxidation-treating stage with a process for producing a magnetic recording medium by subjecting the base material to the film-forming stage in which an Fe3O4 layers is provided on the base material and the oxidation-treating stage in which said Fe2O4 layer is oxidized to gamma-Fe2O3. CONSTITUTION:The 1st layer of a thin Fe3O4 film 2a is deposited by a sputtering method and vacuum deposition method on a base plate 1. The film 2a is then heat-treated in the atmosphere, by which a thin gamma-Fe2O3 film 2a is obtd. The 2nd layer of a thin Fe3O4 film 2b is further deposited by the similar method on the 1st layer of the film 2a and is again heat-treated in the atmosphere, by which the 2nd layer of a thin gamma-Fe2O3 film 2b is obtd. A magnetic recording medium having excellent film quality is obtd. when the film thickness of the 1st layer and 2nd layer is about <=1,000Angstrom . The case of repeating twice the film formation and oxidation treatment of the thin Fe3O4 is explained and the similar effect is obtd. with >=2 times as well.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method of manufacturing a magnetic recording medium capable of high-density recording.

FIG. 1 shows a cross-sectional view of a magnetic recording medium obtained by a conventional magnetic recording medium manufacturing method. In the figure, +11 is the base material (2I is the base material (Fe@04 deposited on 11)
It is a thin film and becomes J) r=Fe snow 08 by oxidation treatment.

That is, F is applied onto the base material (11) by a grasshopper method, a vacuum evaporation method, etc.
) γ-Fe by depositing a Fe@Oa thin film and then heat-treating the Fe,04 thin film in air.

0, a thin film can be obtained.

As the magnetic properties of the magnetic film obtained by the above conventional method, the relationship between the saturation magnetic flux density Bs (KG), coercive force He [KθC], and oxidation treatment temperature To (''C) is shown in Figure 2 (a) and (''C), respectively. b) K is shown. In the figure, (5) is 1000° in terms of film thickness.
A and (B) are the characteristics when the film thickness is 2000'A. As can be seen from the figure, when the film thickness is about 10,000 A, the coercive force and saturation magnetic flux density are constant regardless of the oxidation temperature. On the other hand, at about 2000° A, oxidation is insufficient and the composition becomes non-uniform, so the coercive force and saturation magnetic flux density change greatly.

From the above relationship, the thinner the i thickness, the more oxidation progresses, the more uniform the composition, and the better the magnetic properties of γ-FelOg.
It was discovered that a thin film can be obtained easily under low pressure and with little variation due to processing temperature, leading to this invention.

This invention was made to eliminate the above-mentioned conventional drawbacks, and includes a film formation process for forming an Fe104 layer on a base material, and an oxidation treatment process for oxidizing this Fe104 layer to form γ-FC10 on the same base material. By repeating this several times, oxidation is moderately promoted and γ-Fe@'0@ is uniformly generated.
The object of the present invention is to provide a method for manufacturing a magnetic recording medium exhibiting the excellent magnetic properties inherent to F et Os. FIG. 8 shows a method for manufacturing a magnetic recording medium according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a magnetic recording medium. In the figure, (11 is the base material, (2a) is this base material (
The first layer of Fe, 0.04 thin film deposited on 1) is oxidized to form γ-Fe, 0. It becomes a thin film. (2b) is the second layer of Fe, 04 thin film, which is made of γ-Fel by oxidation treatment.
This becomes an OsN film.

That is, the first Feg04 thin film (2a) is deposited on the substrate (1) by a batter method, a vacuum evaporation method, or the like. Next, by heat-treating the Fe, 04 Hiromi film (2a) in the atmosphere, a pr Fe, o@ thin film (2a) is obtained.

Furthermore, a second layer of Fal104 thin film (2b) was deposited on the first layer of r-Few Os thin film (2a) using the same force method, and the second layer of γ-F was further heat-treated in the atmosphere.
ez(% thin film (2b)) is obtained.

At this time, when the film thicknesses of the first layer and the second layer are about 1000° or less from the results shown in FIG. 2, a magnetic recording medium with excellent film quality can be obtained.

In the above embodiment, a case has been described in which the formation of the Fe, 04 thin film and the oxidation treatment are repeated twice, but the same effects as in the above embodiment can be obtained even if the process is repeated twice or more.

As explained above, the present invention includes a film formation process for forming an Fe3O4 layer on a base material, and an oxidation treatment process for oxidizing this i'e, a, layer to form 1-Fe, Oll on the same base material. By repeating multiple times, oxidation is moderately promoted and γ-
It is possible to obtain a method for manufacturing a magnetic recording medium in which Fe, O, is uniformly generated and exhibits the excellent magnetic properties inherent to γ-FesOs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a magnetic recording medium obtained by a conventional magnetic recording medium manufacturing method, and FIG. (b) is a characteristic diagram showing the relationship between the magnetic properties and the oxidation treatment temperature, and FIG. 8 is a sectional view of a magnetic recording medium obtained by a method for manufacturing a magnetic recording medium according to an embodiment of the present invention. In the figure, (1) is the base material, f2+, (2a), (2
b) is an Fe3O4 thin film with γ-Fe, O
Films that will become Il films, (A) and (B) each have a film thickness of about 1
000'A and approximately 2000X. Note that the same reference numerals in each figure indicate the same or equivalent parts. Agent Masuo Oiwa 141 Figure 3v:i Procedural amendment (voluntary) 1. Indication of the case Japanese Patent Application No. 138454/1983 3, Amended by Representative Hitoshi Katayama (11 The scope of claims in the specification is amended by 9 as shown in the attached sheet. (2) Page 2, line 1 and Correct the words "grasshopper method" in line 17 of page 3 to "sputter method". (3) Lines 9, 11 and 13 of page 2, lines 6 and 5 of page 4. Change “OA” in the 9th line of the page to “
λ”. 7. A document stating the scope of claims after the amendment to the list of attached documents... 1 or more copies Claims (1) A film formation process for forming an Fe3O4 layer on a base material, and oxidizing the Fe3O4 layer. A method for manufacturing a magnetic recording medium, which is subjected to an oxidation treatment step using r Fe2us, and the above-mentioned film formation step and oxidation treatment step are repeated multiple times on the same base material. The method for manufacturing a magnetic recording medium according to claim 1, characterized in that the thickness of the f21 Fe3O4 layer formed at one time is 1000 Å or less.

Claims (1)

[Claims] (11) A film forming process for forming a KFe1104 layer on a base material, and an oxidation to oxidize the 04 layer to 10 g of γ-Fe. A method for manufacturing a magnetic recording medium characterized by repeating the treatment process multiple times on the same base material. (2) The thickness of the Fe204 layer formed at one time is 1000°A.
A method for manufacturing a magnetic recording medium according to claim 1, characterized in that: