JPS60136907A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain a thin film magnetic head which attains high density of recording/reproduction by forming film thickness of an upper magnetic layer to a specific multiple to the film thickness of a lower magnetic layer of the thin film magnetic head. CONSTITUTION:The 1st magnetic substance layer 1 is formed on a substrate 7, furthermore a film 2 functioning as a magnetic gap length is formed and a conductor coil 4 is brought into patterning. An insulator 5 covering the ruggedness of the conductor coil 4 is formed thereon, the 2nd magnetic substance layer 3 is formed so as to cover the conductor coil 4 and the insulator 5 and is patterned to a prescribed shape. Then the film thickness of the 2nd magnetic substance layer is made thicker by 1.4-1.6 times that of the 1st magnetic substance layer 15. The film thickness of the 2nd magnetic substance layer formed by 1.4- 1.6 times that of the 1st magnetic substance layer causes the recording magnetic field distribution to be made steep in this way, and the waveform distortion at reproduction is suppressed to a value below the permissible amount, then the thin film magnetic head attaining the high density recording is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a thin film magnetic head formed using thin film forming techniques such as plating, sputtering, and vapor deposition, and a high precision patterning technique called photolithography.

[Background of the invention]

A typical structure of a thin film magnetic head is disclosed in Japanese Patent Application Laid-Open No. 55-8402.
As described in Publication No. 0, in the magnetic circuit of such a thin film magnetic head, how should the thickness of the magnetic layer exposed on the operating surface of the magnetic head, that is, the thickness of the pole piece and the thickness of the magnetic gap, be determined? The setting is important in increasing data density.

In response to such problems, the present applicant has proposed Japanese Patent Application Laid-Open No. 58-1371.
In No. 20, he focused on the undershoot that occurs on the magnetic head, which is peculiar to thin-film heads, and proposed a thin-film head that can achieve high-density recording by making the second magnetic layer thicker than the first magnetic layer.

In such a thin-film magnetic head, in order to prevent magnetic saturation at the stepped portion and perform higher density recording, the optimal values for the thickness of the first magnetic layer and the thickness of the second magnetic layer must be investigated. The need has arisen.

[Purpose of the invention]

An object of the present invention is to provide a thin-film magnetic head that can optimize the film thickness ratio of the first and second magnetic layers and realize high-density recording and reproduction.

[Summary of the invention]

In order to achieve higher density recording and reproduction, it is necessary to avoid magnetic saturation during recording and make the recording magnetic field distribution steeper.

Therefore, the present invention is characterized in that the thickness of the upper magnetic layer is 1.4 to 1.6 times that of the lower magnetic layer of the thin-film magnetic head.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a thin film magnetic head to which the present invention is applied.
The second magnetic layer 3 has a conductor coil 4 with respect to the first magnetic layer 1.
Since a step is caused by the insulating layer 5, it is necessary to apply a film to the step. Generally, when forming a film on a surface with a certain level difference using techniques such as vapor deposition, sputtering, and plating, the thickness of the film on the sloped part is poor, and the film thickness on the sloped part is smaller than that of the film formed on a flat surface. will also decrease. Therefore, the first
If the thickness of the magnetic layer 1 and the second magnetic layer 3 are made the same, magnetic saturation occurs at the sloped portion 6, and the recording magnetic field from the head decreases, especially for media with high Hc for high-density recording. becomes disadvantageous. Figure 2(a) shows the positional relationship between the thin-film magnetic head and the medium, and Figure 2(b) shows the positional relationship between the thin-film magnetic head and the medium, and Figure 2(b) shows the positional relationship in the in-plane direction of the medium X at a distance Y from the tip of the head to the center of the medium. This figure shows an example of the recording magnetic field distribution in FIG. As described above, when magnetic saturation occurs in the slope portion 6, the side of the second magnetic layer 3 having the slope s6, that is, the traili
An influence of the leakage magnetic field ΔH1 occurs on ng 5ide. On the other hand, Figure 3 shows the thickness ratio T2/T2 of the first magnetic layer thickness T1 and the second magnetic layer thickness T2, the influence of the leakage magnetic field ΔH1 and ΔH2, and the magnetic field H at the center of the gap. This is a calculation of the correlation with the ratio of As can be seen from this figure, ΔH1 becomes zero up to a film thickness ratio of 15;
H2 occurs from about 1.55.

In particular, ΔH1 is a leakage magnetic field of trailing 5itde·, so it is obvious that it is important because it directly affects the magnetic field during recording.

An example of the present invention will now be further described based on the above results. In a thin film abrasion head for a magnetic disk as shown in FIG.
A magnetic layer 1 is formed by sputtering to a thickness of 1.3 μm and patterned into a predetermined shape. Further, an alumina film 2 having a magnetic gap length of 0.7 μm is formed and a planar spiral conductor coil 4 is sputtered and patterned. Excessive insulating material 5 to cover the unevenness of the conductor coil 4
is formed thereon, and a second magnetic layer 3 is formed by sputtering so as to cover the conductor coil 4 and the insulator 5, and is patterned into a predetermined shape. child.

At this time, the alumina film 2 is removed so that the first magnetic layer 1 and the second magnetic layer 3 are magnetically short on the side far from the operating surface of the magnetic circuit. After this, a terminal part is formed (not shown).
, a protective film 8 is applied. Furthermore, a magnetic head element having a predetermined gap depth is formed by cutting. Here, the film thickness of the first magnetic layer 1 is 13 μmK, whereas the thickness of the second magnetic layer 3 is 13 μmK.
Three types of head elements were fabricated with film thicknesses of 1.7 μm, 19 μm, and 22 μm. Using the magnetic head element obtained by such a method, a magnetic disk medium having a coercive force of 350 oe is coated with a spacing of 6.7 μm (1F) and 2.
After recording signals at intervals of 5 μm (2F), each signal was reproduced using Mn-Zn ferrite with a gap length of 0.6 μm. The playback output of 1F and 2F obtained in this way
The reproduction output ratio and resolution (V2F/VIF) were 75% when a head with a magnetic layer thickness ratio of 1.3 (1.7 μr11/1.3 μm) was used. On the other hand, the film thickness ratio is 1.4
5 (1.9μm1.3μm), 1.7 (2,2
When recording using a head with a diameter of 11/1.3 μm), 81% and 80% were obtained, respectively. Nodal membrane thickness ratio 1.45
, 1.7 is found to record at a higher density.

On the other hand, in a signal reproduced by the same thin-film magnetic head after similar recording, as the film thickness ratio increases, even harmonic distortion of the reproduced waveform tends to increase. On the other hand, the second even harmonic component with respect to the fundamental wave component is -33 dB and -30 dB.

-2QdB. That is, when the number exceeds 16, waveform distortion increases and information detection reliability decreases.

As described above, by setting the thickness of the second magnetic layer to 1.4 to 1.6 times the thickness of the first magnetic layer, it is possible to make the recording magnetic field distribution steep, and the waveform distortion during reproduction can be made. Since this can be suppressed to below the allowable amount, a thin-film magnetic head that achieves high-density recording can be realized.

〔Effect of the invention〕

According to the present invention, high-density recording can be easily achieved simply by controlling the thickness of the magnetic film of the thin-film magnetic head.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a thin film magnetic head to which the present invention is applied;
Figure 2 is a diagram showing the positional relationship between the thin film magnetic head and the medium and the magnetic field distribution from the head, and Figure 3 is a diagram showing the relationship between the thickness ratio of the magnetic material on the surface facing the medium and the influence of the flying magnetic field. . 1..First magnetic layer 2..Magnetic gap layer 3..Second
Magnetic layer 4... Tatami coil 5 Insulating layer 6... Diagonal l
Il]s 7..Substrate 8..Retention@film 9..medium (cL) ())) -〇 + χ Figure 3ㅅ.

Claims (1)

[Claims] a first magnetic layer formed on a substrate; a conductor coil formed on the first magnetic layer; and a first magnetic layer sandwiching the conductor coil between the first magnetic layer and the first magnetic layer. a second magnetic layer having a magnetic gap on the surface facing the recording medium and magnetically short-circuited with the first magnetic layer on the side opposite to the surface facing the recording medium; an insulating layer that electrically insulates the first and second magnetic layers, and the second magnetic layer has a thickness of 1A to 1.6 with respect to the first magnetic layer.
A thin-film magnetic head characterized by being twice as thick.