JP2765050B2 - Magnetic recording media - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, for example, a magnetic recording medium used in a magnetic disk drive.

2. Description of the Related Art At present, most magnetic disks used as magnetic recording media are oxide-coated media, and a recording medium having a metal thin-film magnetic layer formed by plating or sputtering has been attracting attention as a means for improving the recording density. Have been.

However, as the metal thin film medium, a Co-based alloy is mainly used, and the corrosion resistance is not sufficient. Therefore, in general, in a metal thin film medium, in order to improve corrosion resistance,
A protective film is formed on the metal thin-film magnetic layer. It is also necessary that the protective film have abrasion resistance. In order to increase the recording density, it is preferable that the magnetic head be as close as possible to the surface of the metal magnetic film. The thinner the protective film, the better.

Conventionally, as this kind of protective film, a metal thin film (Rh, Au, Cr, Ni-P, etc.) formed by wet plating, an oxide film (a film obtained by oxidizing the surface of a metal magnetic film, SiO2, etc.), a nitride film Hard films such as material films (such as Si3N4) and carbide films (such as SiC) have been proposed.

Among these protective films, there are some protective films having considerably excellent corrosion resistance and wear resistance. For example, in order to increase the recording density, a two-layer protective film having a thickness of 50 nm or less (a chromium oxide film having better corrosion resistance in the lower layer and a SiO2 film in the upper layer) has been proposed. (Japanese Patent Application Laid-Open No. Sho 58-177528) Further, as disclosed in Japanese Patent Application Laid-Open No. Sho 61-82321, a Cr film is formed on a metal magnetic film, and a carbon film is formed on the Cr film.

Problems to be Solved by the Invention Although the above-described protective film can secure any corrosion resistance, the thinner the film thickness, the lower the corrosion resistance, and the longer the use time, the more the corrosion. Therefore, when the protective film is thinned in order to shorten the distance between the magnetic head and the magnetic film with the increase in the recording density of the magnetic recording medium, the above-mentioned protective film cannot secure sufficient corrosion resistance. Had a point.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a method in which a chromium body-centered cubic crystal structure is formed on a metal magnetic film by X-ray diffraction (110).
The ratio of the peak intensity of the (211) plane to the peak intensity of the plane is 2
Coat a chromium film that is between 0% and 25%.

Action With this configuration, the ratio of the (211) plane in the chromium film can be increased.

FIG. 1 is an enlarged sectional view showing a magnetic recording medium according to an embodiment of the present invention. In FIG. 1, a 20 μm-thick Ni—P electroless plating base film 2 is formed on a disk substrate 1 made of an aluminum alloy, and a Co—Ni 20 metal magnetic film 3 having a Cr base is formed thereon. Is formed thereon, and the ratio of the peak intensity I (110) of the (110) plane to the peak intensity I (211) of the (211) plane by X-ray diffraction of a 10 nm thick chromium body-centered cubic crystal structure, I (211) ) / I (110) value is 0.20 ~
A chromium film 4 having a thickness of 0.25 is formed thereon, and a carbon film 5 having a thickness of 20 nm is further formed thereon to secure abrasion resistance.
A lubricating film 6 of 5 nm fluorine-based oil is coated.

The chromium film was formed by an RF sputtering method. However, X-ray diffraction of the chromium body-centered cubic crystal structure (110)
The ratio of the peak intensity I (211) of the (211) plane to the peak intensity I (110) of the plane, and the value of I (211) / I (110) is 0.20 to 0.2
In order to obtain a chromium film of 5, an appropriate sputtering power, sputtering pressure and substrate temperature are required. As an example, the intensity ratio between the peak of the (110) plane and the peak of the (211) plane of the chromium body-centered cubic crystal structure by X-ray diffraction when the sputtering pressure is 3 mmTorr and the substrate temperature is 90 ° C. This shows the relationship with the value of I (211) / I (110). As can be seen from FIG. 2, under this condition, the sputter power is almost 30.
The value of I (211) / I (110) in the range of 0W to 800W is 0.20 ~ 0.2.
It is 25. Also, the sputter power, the sputter pressure, and the substrate temperature must be set for each sputter device.

FIG. 3 shows the ratio of the peak intensity I (110) on the (110) plane to the peak intensity I (211) on the (211) plane by X-ray diffraction of the chromium body-centered cubic crystal structure, I (211) / I (110). 4) shows the relationship between the value of ()) and the amount of increase in the location where a missing pulse error occurs.
This is because the chromium body-centered cubic crystal structure X
(110) plane peak intensities I (110) and (21)
1) The ratio of the peak intensity I (211) of the plane, I (211) / I (110)
A chromium film with a thickness of 10 nm different from each other is coated by sputtering.
After performing an environmental test for 0 hours, a portion where a missing pulse error occurred was measured. In FIG. 3, point 1 is a sputter power of 500 W, a substrate temperature of 0 ° C., and the power supply is DC. Point 2 is a sputter power of 500 W, a substrate temperature of 90 ° C., and the power supply is DC. Point 3 is a sputter power of 200 W, a substrate temperature of 90 ° C. Power is RF, point 4 is sputter power 1000W, substrate temperature 90 ° C, power is RF, point 5
Is a sputtering power of 500 W, a substrate temperature of 150 ° C., and the power supply is RF. Point 6 is a sputtering power of 700 W, a substrate temperature of 90 ° C., and the power supply is RF.
Point 7 is that a chromium film is formed on the magnetic layer by sputtering power of 500 W, substrate temperature of 90 ° C., and power supply of RF, and the number of locations where a missing pulse error occurs after the environmental test is measured. From the measured number, The number obtained by subtracting the number of locations where a missing pulse error has occurred before the environmental test was performed is plotted on the vertical axis. As shown in FIG. 3, the peak intensity I (11) of the (110) plane by X-ray diffraction of the chromium body-centered cubic crystal structure
0) and (211) plane peak intensity I (211) ratio, I (211)
When the value of / I (110) is 0.20 to 0.25, it shows excellent corrosion resistance that there is no increase in the number of missing pulse error locations.

A magnetic disk medium having high corrosion resistance was obtained by the high corrosion resistance chromium film. In particular, the thicknesses of the highly corrosion-resistant chromium film 4, the protective film 5, and the lubricating film 6 are 10 nm, 20 nm, respectively.
A magnetic disk with excellent corrosion resistance, abrasion resistance, and low abrasion resistance could be produced even with an extremely thin protective film having a thickness of 5 nm and a total thickness of 35 nm.

Advantageous Effects of the Invention The present invention provides a method for producing a chromium body-centered cubic crystal structure on a metal magnetic film, which has a (21) peak intensity of (110) plane by X-ray diffraction.
1) By coating a chromium film with a surface peak intensity ratio of 0.2 or more, the ratio of the (211) surface in the chromium film can be increased, resulting in excellent corrosion resistance and poor environment. Among them, corrosion of the metal magnetic film can be prevented for a long time.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of a magnetic recording medium according to an embodiment of the present invention, and FIG. 2 is a peak intensity I (110) and (211) of a (110) plane by X-ray diffraction of a chromium body-centered cubic crystal structure. FIG. 3 is a graph showing the relationship between the ratio of the surface peak intensity I (211), the value of I (211) / I (110), and the sputter power.
1) A graph showing the relationship between the value of / I (110) and the number of missing pulse errors before and after the test. DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Base film 3 ... Metal magnetic film 4 ... Chromium film 5 ... Protective film 6 ... Lubricating film

Claims (1)

(57) [Claims] A metal magnetic film is provided on a substrate, and a chromium body-centered cubic crystal structure is formed on the metal magnetic film by X-ray diffraction.
A magnetic recording medium comprising a chromium film having a ratio of the peak intensity of the (211) plane to the peak intensity of the (0) plane being 20% to 25%.