JPS63253501A - Magnetic recorder - Google Patents

Abstract

PURPOSE:To hold the deterioration in an overwrite erasing rate at an extremely small value by a change in ambient temp. by providing a magnetic recording medium which consists essentially of Co and Cr and is added respectively specific ratios of Zr or Hf or Ta. CONSTITUTION:The magnetic recording medium which consists essentially of Co and Cr and is added respectively with 1.2-2.0at.% or 1.3-2.3at.% or 1.5-2.5at.% Zr or Hf or Ta is provided. The temp. coefft. of the coercive force approximate to the temp. coefft. of the saturation magnetic flux density of 'SENDUST(R)' is thereby provided to the magnetic recording medium. The temp. change dy/dT of a recording depth y attains dy/dTproportional aBS-aHC if the temp. coefft. aBS of the saturation magnetic flux density of a head and the temp. coefft. aHC of the coercive force of the medium are set at the approximate values in such a manner and, therefore, the magnetic recorder which is less changed in recording depth by temp. is formed. The deterioration of the over write erasing rate is thus extremely minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic recording device, such as a flexible disk or a hard disk, that rewrites data by overwriting without erasing.

(Conventional technology) FIG. 4 is a conceptual diagram of a conventional override.

By overwriting a new signal 4 on top of the signal 6 recorded on the medium 1 using the head 2 with a wider gap length, the previous signal is simultaneously erased. Even if the size of the recording area 3 changes somewhat due to changes in temperature, etc., a sufficient erasing rate can be obtained because it reaches the bottom of the medium.

(Problems to be Solved by the Invention) The above-mentioned override functioned without problems in an apparatus with a low recording density, that is, with a wide head gap length and capable of performing saturation recording sufficiently to the bottom of the medium.

On the other hand, in perpendicular magnetic recording using a single-layer perpendicular medium and a ring head, good recording and reproducing characteristics are obtained by combining a narrow gap head that can obtain a steep writing magnetic field and a relatively thick medium (IEICE (Recording on a vertically anisotropic film using a MR81-8f ring head). With such a combination, it is difficult to perform saturation recording to the bottom of the medium, resulting in near-surface recording.

The problem at this time is ensuring the override erasure rate. By selecting the magnetic properties of the medium, it is possible to secure an override erasure rate of about -28 dB even for surface recording (
2), but when the coercive force of the medium and the saturation magnetic flux density of the head change with temperature, the recording depth changes as shown in FIG. 3, and the override erasing rate deteriorates due to the unerased signal 5. (The 10th Japanese Society of Applied Magnetics Academic Lecture Abstracts 5
aA-9) The purpose of the present invention is to eliminate such drawbacks,
It is an object of the present invention to provide a magnetic recording device whose override erasure rate does not deteriorate even if the operating temperature changes.

(Means for Solving the Problems) The magnetic recording device of the present invention has a magnetic head in which the vicinity of the gap or the entire core is made of a Sendust alloy, and the main components are Co and Cr, and 1.2 to 2.0 at% Zr, 1.
The recording medium is characterized in that either 3 to 2.3 at% Hf or 1.5 to 2.5 at% Ta is added.

(Function) By adding such additives, the temperature coefficient of coercive force, which was 10.34%/deg in the CoCr film, became the first.
It changes as shown in the figure. The broken line in the figure indicates the temperature coefficient of the saturation magnetic flux density of Sendust -0.11%/deg. By adding the amount as described above, the medium has a temperature coefficient of coercive force close to the temperature coefficient of the saturation magnetic flux density of Sendust. If the temperature coefficient QBs of the saturation magnetic flux density of the head and the temperature coefficient αHe of the coercive force of the medium are set to values close to each other in this way, the temperature change dy/dT of the recording depth y becomes It is possible to create a magnetic recording device with little change in . Therefore, the third
The deterioration of the override erasure rate as shown in the figure can be extremely minimized.

(Example) Examples and reference examples of the present invention are shown below. The medium is 20
Zr, H on top of CoCr alloy target with at%Cr
f.

A Ta pellet was placed and produced by RF magnetron sputtering. Table 1 shows the additives and their amounts in Examples and Reference Examples, the temperature coefficient of coercive force, the override erasure rate (0/W25) at 25°C measured with a Sendust head with a gap length of 0.3 pm, and 10° Write at 50°C
Override erasure rate (0/WI
Q-5Q), the override erasure rate (0/W50-1o) when writing at 50°C and overwriting at 10°C is summarized. To explain the measurement method, first 50k
A FRPI signal was written, a 22 kFRPI signal was overwritten, and the amount of attenuation of the 50 kFRPI signal due to overwriting was taken as the override erasure rate. In order to serve as a device, O/W25, O/W10-50. O/W
50-1o must be less than 126 dB.

In the example, the temperature coefficient is that of Sendust's saturation magnetization (-
O/W10 is within the range of ±0°04%/deg (range indicated by the dotted line in Figure 1).
-5Q.

01/w5o10 does not deteriorate significantly compared to O/W25, but in the reference example of CoCr and those with a small amount of added elements, 0/W50-IQ deteriorates to exceed -26 dB. (Effects of the Invention) As described above, in the magnetic recording device of the present invention, even in surface recording, deterioration in the override erasure rate due to changes in ambient temperature can be suppressed to an extremely low level.

[Brief explanation of drawings]

Figure 1 shows CoCrZr and CoCrH depending on the amount of added elements.
f. FIG. 3 is a diagram showing changes in the temperature coefficient of coercive force of CoCrTa. FIG. 2 is a conceptual diagram of override when the present invention is implemented. FIG. 3 is a conceptual diagram of an override of a device manufactured ignoring temperature characteristics. FIG. 4 is a conceptual diagram of overriding in a conventional device. In the figure, 1...recording layer of medium, 2...head 3...recording area, 4...new signal 5...signal remaining after erasing, 6...
...Already recorded signal Fig. 1 addition amount [at%l Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Scope of Claims] (1) In a magnetic recording device configured with a magnetic head in which the vicinity of the gap or the entire gap is made of a Sendust-based alloy and a magnetic storage medium whose main components are Co, Cr, and Zr, Zr in the magnetic recording medium A magnetic recording device characterized in that the content of is 1.2 to 2.0 at%. (2) In a magnetic recording device configured with a magnetic head in which the vicinity of the gap or the entire gap is made of a Sendust-based alloy and a magnetic recording medium whose main components are Co, Cr, and Hf, the content of Hf in the magnetic recording medium is 1. A magnetic recording device characterized in that the concentration is 3 to 2.3 at%. (3) In a magnetic recording device configured with a magnetic head in which the vicinity of the gap or the entire gap is made of a Sendust-based alloy and a magnetic recording medium whose main components are Co, Cr, and Ta, the Ta content in the magnetic recording medium is 1. A magnetic recording device characterized in that the concentration is 5 to 2.5 at%.