JPS63257901A - Magnetic recorder - Google Patents

Abstract

PURPOSE:To prevent deterioration in an overwrite erasing rate in spite of a change in service temp. by specifying the content of Zr in a magnetic recording medium. CONSTITUTION:This recorder consists of a magnetic head which consists of an alloy contg. Co, Zr and Nb as essential components near a gap or over the entire part of a core and a recording medium which consists essentially of Co and Cr and is added with any among 1.9-3.0at.% Zr, 2.1-3.5at.% Hf and 2.1-3.5at.% Ta. The medium having the temp. coefft. of the coercive force approximate to the temp. coefft. of the saturation magnetic flux density of 'SENDUST(R)' is obtd. by specifying the amt. of the component to be added to the above-mentioned medium. The magnetic ercorder which is less changed in recording depth by temp. is thereby obtd. and the deterioration in the overwrite erasing rate by a temp. change is lessened.

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 onto a vertically anisotropic film using a MR81-8r ring head J). 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 by matching the characteristics of the magnetic head with the characteristics of the magnetic recording medium, and to provide magnetic recording in which the override erase rate does not deteriorate even if the operating temperature T changes. The goal is to provide equipment.

(Means for Solving the Problems) The magnetic recording device of the present invention includes a magnetic head in which the vicinity of the gap or the entire core is made of an alloy mainly composed of Co, Zr, and Nb, and a magnetic head mainly composed of Co and Cr. 1°9~3
．． 0 at% Zr, 2.1-3.5 at% Hf, 2.1
The recording medium is characterized in that it has a structure in which Ta is added in an amount of 3.5 at% to 3.5 at%.

(Function) By adding such an additive, the temperature number of the coercive force, which was -0.34%/deg in the CoCr film, changes as shown in FIG. The broken line in the figure indicates the temperature coefficient of the saturation magnetic flux density of CoZrNb -0,032%/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. In this way, the temperature coefficient GB of the saturation magnetic flux density of the head is
If S and the temperature coefficient αHC of the coercive force of the medium are close to each other, the temperature change dy/dT in the recording depth y becomes y □ αBS - αHe T, so there is little change in the recording depth due to temperature. A magnetic recording device is created. 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 pellet of RA 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 CozrNb head with a gap length of 0°3 pm, and 10° d cell writing 50°
Override deletion when overwriting with C (0/WI
O-50), override erasure (0/W5010) when writing at 50°C and overwriting at 10°C. To explain the measurement method, first, 50kFR.
A PI signal was written and stored, 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. To serve as a device, 0/W2s, O/WIQ 5Q, O/W5
Both Q and IQ must be less than 126 dB.

In the example, the temperature coefficient of the coercive force of the medium is within the range of ±0.04%/deg (the range indicated by the dotted line in Figure 1) with respect to that of Sendust's saturation magnetization (-0.032%/deg). O/W10-50, O/W50-10 is O/W2
Although it does not deteriorate significantly compared to Co. 5, the reference example Co
If the amount of Cr or additive elements is small, the O/W50-10 deteriorates and exceeds -26 dB.

In addition, CoZr is applied to a part or the whole of the magnetic herad core.
Although a Nb alloy is used, even if other additive elements are added to this alloy and the composition ratio is changed, the temperature coefficient of saturation magnetization remains within a range close to that of this example (±0.04%/deg) (in accordance with the invention). Effects) 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 small extent.

[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 foil Figure 1 Addition amount rat%] Figure 2 Figure 3 Figure 4

Claims (3)

[Claims] (1) A magnetic head in which the vicinity of the gap or the entire core is made of an alloy whose main components are Co, Zr, and Nb;
1. A magnetic recording device configured with a magnetic storage medium containing Cr and Zr as main components, characterized in that the content of Zr in the magnetic recording medium is 1.9 to 3.0 at%. (2) A magnetic head in which the vicinity of the gap or the entire core is made of an alloy whose main components are Co, Zr, and Nb;
1. A magnetic recording device configured with a magnetic recording medium containing Cr and Hf as main components, characterized in that the content of Hf in the magnetic recording medium is 2.1 to 3.5 at%. (3) A magnetic head in which the vicinity of the gap or the entire core is made of an alloy whose main components are Co, Zr, and Nb;
1. A magnetic recording device configured with a magnetic recording medium containing Cr and Ta as main components, characterized in that the content of Ta in the magnetic recording medium is 2.1 to 3.5 at%.