JPH02201722A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To surely prevent the waving by a shape effect with simple constitution and to enhance performance by providing a specific recessed part in the side part of a recording track on the side opposite to a gap layer side. CONSTITUTION:The recording track having the recessed part 15a which is about half the track thickness P in the track thickness direction and is about half the track width TW in the track width direction is provided in the side part of the recording medium sliding surface of a thin magnetic film 15 on the side opposite to the gap layer side thereof. The head equiv. to the head having the track of the track thickness P and about half the track width TW and the track of about half the track thickness P and about half the track width TW is constituted in such a manner. The waving by a shape effect is surely prevented with simple constitution and the performance is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a thin film magnetic head used, for example, in a magnetic disk drive for a computer.

(Prior Art) Generally, a thin film magnetic head is made of Mn-
A gap layer 2 such as 8102 is formed by vapor deposition on a magnetic material 1 constituting the lower core such as Zn ferrite or N, -Z, ferrite, etc., and an insulating layer 3,
After a conductive layer 4 made of Cu or the like and an insulating layer 5 which will become a coil are formed in this order, a magnetic thin film 6 made of Permalloy or Sendust or the like which constitutes the upper core is laminated. Then, on this magnetic thin film 6, a holder 8 made of glass or the like is placed on an adhesive layer 7.
A magnetic thin film 6 is attached to the recording medium sliding surface.
A recording track is formed by arranging these with a track width Tw and a track thickness P corresponding to the gap layer 2.

However, in a thin film magnetic head, the track thickness P of the recording track is very small, about several μm, so the track thickness P is smaller than the shortest recording wavelength λmin in high-density recording.
When it becomes approximately the same as the value, there is a problem in that the so-called contour effect causes a waving phenomenon in which the shortest recording wavelength λ, which is a high-frequency component in the frequency band used, occurs, resulting in a decrease in performance. . That is, in the thin film magnetic head, there is no problem with the pole length of the magnetic body 1 because it is sufficiently thick compared to the shortest recording wavelength λmin, but the track thickness P of the recording track, which is the pole length of the magnetic thin film 8, is The small size of μm poses a problem. Therefore, if the frequency of the recording signal is f1, the recording wavelength is λ, and the relative speed with respect to the recording medium is V, then the relationship between them is Vfλ, and as shown in Figure 7, P is compared to λmin. If it is sufficiently large, the frequency characteristic F will be as shown by the broken line in the figure, but if P and λmin become approximately the same, a waving phenomenon will occur as shown by the solid line F1. This waving phenomenon occurs when f is approximately V/
2P, approximately 2v/2P.

It occurs approximately in the order of 3v/2P, the output is large at the first v/2P, becomes small at the next 2v/2P, and then the next 3v/2P.
It becomes larger at v/2P. This means that if the recording medium sliding direction is the y-axis as shown in FIG. The y-axis, which is approximately perpendicular to the axis, is y-0, the surface of the recording medium sliding surface).

This characteristic A is based on the gap layer 2 at the edge of the recording track.
A magnetic field is generated in the opposite direction.

On the other hand, if the X-axis direction component of the residual magnetization of the recording medium is IX, the magnitude of the reproducing magnetic flux is proportional to f-]Hx I X dx according to the reciprocity theorem. Therefore, the distribution of IX becomes large when P is an odd multiple of λ/2, and becomes small when P is an even multiple of λ/2, resulting in a waving phenomenon.

(Problems to be Solved by the Invention) As described above, conventional thin-film magnetic heads have a problem in that waving occurs due to shape effects and performance deteriorates.

The present invention has been made in view of the above circumstances, and provides a thin-film magnetic head that has a simple structure, reliably prevents the waving phenomenon caused by shape effects, and achieves high performance. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) The present invention comprises sequentially laminating a gap layer, a conductor layer, an insulating layer and a magnetic thin film layer on a magnetic material, and a recording sliding surface corresponding to the gap layer. In a thin film magnetic head comprising a recording track formed of the magnetic thin film and having a track width and a track thickness, approximately the track thickness is provided on the side opposite to the gap layer side of the recording track in the track thickness direction. 1/
2, and has a concave portion having a total length of about 1/2 of the track width in the track width direction.

(Function) According to the above configuration, there is a recording track having a track thickness of about 1/2 of the track width, and a recording track having a track thickness of about 1/2 and about 1/2 of the track width. By configuring equivalent heads, the waving phenomenon of frequency characteristics occurring in these recording tracks is canceled out. Therefore, it is possible to prevent the occurrence of a waving phenomenon in the frequency characteristics.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and FIG.
is a diagram showing a recording medium sliding surface, and FIG. 10B is a cross-sectional view of FIG. That is, figure [1i 10 is Mn-
A magnetic material constituting the lower core such as Zn ferrite or N, -Zn ferrite.
A gap layer 11 such as 102 is formed by vapor deposition or the like. Then, on this gap layer 11, an insulating layer 12, a conductor layer 13 such as Cu that will become a coil, and an insulating layer 14 are formed in this order, and then a magnetic thin film 15 such as Permalloy or Sendust that forms the upper core is laminated. Ru. A holder 16 made of glass or the like is attached to the magnetic thin film 15 via an adhesive layer 17, and the magnetic thin film 15 is attached to the recording medium sliding surface.
A recording track is formed by arranging these with a track width Tw and a track thickness P corresponding to the gap layer 11. On this occasion,
A recess 15a of about P/2 in the track thickness direction and about Tv/2 in the track width direction is formed on the recording track formed by the magnetic thin film 15 by chemical etching using photolithography or the like or physical etching using plasma or the like. They are formed at predetermined intervals using a targeted etching method or the like. The recess 15a is formed with a dimension of, for example, about P/2 in the depth direction of the recording medium sliding surface, which does not impair the characteristics of the thin film.

In the above configuration, the recording track is equivalent to a track having a track thickness P and a track width Tv/2 and a track having a track thickness P/2 and a track width Tw/2. As a result, as shown in FIG. 2, in the portion of track thickness P, the frequency f becomes v/2P, 2v/2
Large and small peaks are repeated in the order of P, 3v/2P-.... On the other hand, in the part with track thickness P/2, v/P, 2 v/P, 3 v/
Large and small peaks are repeated in the order of P.... As a result, as shown in FIG. 3, the output from the recording track has a peak of about 1/2 of the conventional peak at v/2P when compared with the conventional frequency characteristic F1, and the output from the recording track becomes v/2P.
The magnitude is canceled by P, the peak disappears, and 3 v/
2 P reduces the peak to about 1/2, and
Frequency characteristic F2 with a small peak starting at v/P
(Indicated by the dotted chain line in the figure).

In this case, the small peak at 2 v/P becomes a high-order peak, and the small peak value causes no problem.

In this manner, the thin film magnetic head has approximately 1/2 of the track thickness P in the track thickness direction on the side of the recording medium sliding surface of the magnetic thin film 15 opposite to the gap layer 12 side, and A recording track having a recess 15a of about 1/2 of the track width Tw in the track width direction is provided, and a track with a track thickness P of about 1/2 of the track width Tw and a track with a track thickness P
By configuring a head equivalent to having a track with approximately 1/2 of the track width Tv, the waving phenomenon of frequency characteristics that occurs in these recording tracks is canceled out between each other, and the waving phenomenon Attempts are being made to prevent the occurrence of

Further, in the above embodiment, the recording track has a recess 1 of approximately P/2 in the track thickness direction and approximately Tw/2 in the track width direction.
Although the explanation has been given for the case where 5a is provided, it is not limited to this.
For example, as shown in FIG. 4, a plurality of recesses 20a and 20b are provided in the track width direction at P/2 in the track thickness direction,
It is also possible to configure the recesses 20a, 20b so that the total length in the track width direction is approximately Tv/2, and similar effects can be expected.

Further, in the above embodiment, the lower core is formed of the magnetic material 10 using ferrite, but is not limited to this. For example, as shown in FIG. It is also possible to configure using a lower core. In this case, in order to prevent the undulating phenomenon in the lower core, a recess 30a with a gap of P/2 in the track thickness direction and Tw/2 in the track width direction is formed in the magnetic thin film 30 constituting the magnetic body, similarly to the recording track. It may be provided facing the opposite side to the layer 11.

Therefore, it goes without saying that the present invention is not limited to the above embodiments, and that various modifications can be made without departing from the spirit of the invention.

[Effects of the Invention] As detailed above, the present invention provides a thin film that has a simple structure, reliably prevents the waving phenomenon caused by shape effects, and achieves high performance. A magnetic head can be provided.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a thin film magnetic head according to an embodiment of the present invention, FIGS. 2 and 3 are diagrams shown to explain the operation of FIG. 1, and FIGS. Figures 6 to 8 showing other embodiments of the invention are diagrams shown to explain problems with conventional thin film magnetic heads. 10... Magnetic material, 12... Gap layer, 12...
Insulating layer, 13... Conductor layer, 14... Insulating layer, 15.
...magnetic thin film, 15a...recess, 16...holder 17...adhesive layer, 20...a, 20b...recess,
30...Magnetic thin film, 30a...Concave portion, 31...Adhesive layer, 2...Holder (Figure)

Claims (1)

[Claims] A gap layer, a conductor layer, an insulating layer, and a magnetic thin film layer are sequentially laminated on a magnetic material, and a track width and track thickness are formed on the recording sliding surface by the magnetic thin film corresponding to the gap layer. In a thin film magnetic head, a thin film magnetic head is provided with a recording track having a thickness of approximately 1/2 of the track thickness in the track thickness direction on a side opposite to the gap layer side of the recording track; A thin film magnetic head characterized in that a recessed portion having a total length of approximately 1/2 of the track width is provided in the magnetic head.