JPS6220118A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain a thin film magnetic head which can reproduce signal magnetization of a high density by microminiaturizing magnetic paths to the extreme according to this invention. CONSTITUTION:The 1st thin film coil 7 itself constitutes one turn of a closed loop and intersects with the 1st magnetic path 9 consisting of a thin film magnetic detecting part 8. The 2nd lower thin ferromagnetic film 13 and 2nd upper thin ferromagnetic film 14 between which the rear of the 1st thin film coil 7 is inserted so as to constitute the 2nd magnetic path 16 intersecting with the coil 7 are laminated on the rear of the part 8 on a thin film forming surface 2. Both the front and rear ends thereof are joined to each other to constitute the closed loop. Plural turns of the 2nd thin film coil 15 are further formed so as to intersect with the 2nd magnetic path 16 and the front part thereof penetrates between the films 13 and 14 on the rear part of the coil 7. Thus the 1st thin film coil 7 and the 2nd thin film coil 15 respectively as the primary and secondary windings of a transformer constitute a step up transformer part 17.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin film magnetic head suitable for efficiently recording and reproducing high-density signal magnetization.

BACKGROUND OF THE INVENTION Magnetic recording technology has made remarkable progress in recent years, and in particular, the recording density per unit area is increasing logarithmically year by year. Such high density is achieved by shortening the wavelength of the signal magnetization and narrowing the track of the recording pattern, and at present, a wavelength of about 1 μm and a track width of about 20 μm are being put into practical use. In order to cope with this increase in density, the efficiency of the magnetic head is increased by making it as small as shown in Figure 5, and the gap length can be narrowed to about 0.3 μm to efficiently reproduce short wavelength magnetization. That's what I do. On the other hand, thin film magnetic heads have been attracting attention in recent years. An example is shown in FIG. 6, where a magnetic pole Q9 made of a ferromagnetic thin film and a thin film coil (vc2) with multiple turns are formed on a non-magnetic substrate CJ using thin film formation technology and photolithography technology, and a substantially ring-shaped thin film is formed. Constitutes a magnetic head. Such thin-film magnetic heads are manufactured using narrower gap manufacturing technology.
Suitable for narrowing tracks.

Problems to be Solved by the Invention Currently, there is a demand for recording and reproducing signal magnetization with even shorter wavelengths. For example, metal evaporated media have a wavelength of around 0.5 μm, and perpendicular magnetic recording, which has recently been attracting attention, has a bit length of 0.15.
Signal magnetization around μm is handled. When reproducing such high-density magnetization with a ring-type head, an ultra-narrow gap of around 0.1 μm is required in consideration of gap loss. On the other hand, with the bulkhead shown in Figure 5, there is a limit to the miniaturization of the magnetic path due to limitations due to processing technology and the need for space to wind bulk windings with a diameter of about 30 μm. As a result, leakage at the gap increases rapidly, recording and reproducing efficiency decreases significantly, and at the same time, it is difficult to accurately form a narrow gap. On the other hand, in a thin film magnetic head like the one shown in Figure 6, the magnetic poles and gaps are laminated using thin film formation technology, so it is easy to form narrow gaps with high precision, but it is difficult to obtain the signal output necessary for circuit processing. Thin film carp/L/CI! 6) needs to be formed into a plurality of turns, and the structure of the magnetic path becomes elongated as shown in the figure due to manufacturing technology. In such a structure, the signal magnetic flux reproduced in the gap does not completely pass through the magnetic path made of the ferromagnetic thin film (two ferromagnetic films), but gradually leaks through the thin film coil part in the middle, and at the same time, the magnetic path as the magnetic head is Although it is smaller than the bulk type, since the core becomes thinner, the magnetic resistance increases, so the magnetic path is relatively smaller and the efficiency is lower, especially when narrowing the gap. The problem was that it became more noticeable.

Therefore, it is an object of the present invention to provide a thin film magnetic head that can efficiently record and reproduce ultra-high density signal magnetization as described above.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a first magnetic path constituting a substantially ring-shaped thin film magnetic detection section on the surface of the substrate, and a chain connected to the first magnetic path. A first thin film coil that intersects and forms a closed circuit by itself, a second magnetic path that interlinks with this first thin film coil, and a first thin film coil that interlinks with this second magnetic path. The second thin film coil is wound more times than the first thin film coil.

Effect The present invention has the above-described configuration, which minimizes the first magnetic path as a signal magnetic flux detection unit to the utmost limit, and has a sufficiently high conversion efficiency to an electric signal even when the gap is narrowed, and on the other hand, the absolute output due to the low number of turns. This deficiency can be compensated for by a step-up transformer consisting of a first thin film coil, a second magnetic path, and a second thin film coil, thereby making it possible to efficiently reproduce high-density signal magnetization.

Example A first embodiment of the invention is shown in FIG. 1a1b.

In the figure, (1) is a non-magnetic head substrate made of ceramic or the like, (2) is its thin film forming surface, and (3) is its recording medium contacting surface. A first lower ferromagnetic thin film (4), a first upper ferromagnetic thin film (5), and these thin films (4) and (5) are disposed at the front end on the recording medium side of the thin film forming surface (2). A first thin film coil (7) having a non-magnetic thin film (6) such as S/SiO□ which forms a magnetic gap at the front end in between, and a portion penetrating between the ferromagnetic thin films (4) and (5) behind it. are arranged in a laminated manner, and a flat folded ring-shaped thin film magnetic detection part (8) is formed from these laminated parts, and its front part including the gap (6) is brought into contact with the recording medium (121). In this case, in order to operate as a ring-type head, it is necessary to make the magnetic gap length sufficiently thinner than the ferromagnetic thin film that constitutes the magnetic pole.The first thin film coil (7) is made of a highly conductive metal such as A/ or Au. It constitutes a closed loop of one turn by itself, and the thin film magnetic detection section (8)
It interlinks with the first magnetic path (9) consisting of.

Furthermore, the thin film magnetic detection section (
8), the coil/1' (77
The second lower ferromagnetic thin film αJ sandwiching the rear part of the second upper ferromagnetic thin film is laminated, and both front and rear ends thereof are joined to form a closed loop. Further, a second magnetic path (second thin film coil Vα9 interlinking with 161) is formed with a plurality of turns, and its front part is connected to the first thin film coil zL/(
7] on the rear part of the ferromagnetic thin film α311 (piercing between t41. This makes the first thin film coil) v (7)
and the second thin film coil/L' (15) are used as the primary and secondary windings of the transformer, respectively, in the step-up transformer section (17).
).

In the above configuration, a series of ferromagnetic thin films are permalloy,
Sendust, amorphous magnetic thin film, etc., and materials suitable for each part are used. For example, the thin film magnetic detection section (8)
As the ferromagnetic thin film used for the recording medium, it is desirable to use sendust or amorphous magnetic thin film, which has excellent wear resistance against running of the recording medium, and as the ferromagnetic thin film for the step-up transformer α force, permalloy, which is easy to form a thick film pattern, is preferable. Are suitable. Note that in the recording medium (121), α@ is a magnetic layer, and aD is a bake layer.

The operation of the thin film magnetic head having the above configuration is that during reproduction, the signal magnetic flux from the signal magnetization recorded on the recording medium (12+ magnetic layer α0) is picked up by the magnetic gap part of the thin film magnetic detection part (8). By guiding the coil to the first magnetic path (9), an electromotive force proportional to the change over time is generated in the first thin film coil (7) interlinked with the coil, and a signal current flows through the coil. This current flows to the step-up transformer section (17
1 transformer is excited, and the z-th transformer secondary winding is
An electromotive force corresponding to the step-up ratio is generated at the terminal (17+) of the thin-film coil U of the thin-film coil U, and a signal output voltage is obtained. During recording, the signal is transferred from the tip of the gap of the thin-film magnetic detection section (8) through the reverse process of the above operation. A recording magnetic field is applied to the recording medium.

By adopting such a structure, the thin film magnetic detection section (8
) can be made as small as possible, so even if the gap length is made extremely narrow, around 0.1 μm or smaller, the signal magnetic flux from the recording magnetization can be converted into an electrical signal with extremely high efficiency. Furthermore, the signal output necessary for circuit processing can be obtained with a highly efficient step-up transformer. In this example, a highly efficient step-up transformer is realized by increasing the thickness of the ferromagnetic thin film that constitutes the transformer, and by designing the longitudinal ratio of the cross-sectional shape where the thin film coils are interlinked to be as equal as possible. be able to.・Figure 2 shows a second embodiment of the present invention, in which the second lower ferromagnetic thin film (13a) is formed over an area wider than the outermost periphery of the step-up transformer section (171). The rear parts of the first thin film coil lv (15) and the second thin film coil 1v (15) are arranged so as to be aligned with each other, and the second upper ferromagnetic thin film (
14a) has a downward recess for surrounding the rear side of these coils (7), in cooperation with the lower ferromagnetic thin film (13a), and a second thin film coil (covering the upper surface of the front side of 19). Therefore, the second upper ferromagnetic thin film (14
a) is the central part of the second thin film coil /L/(15) and the first and second thin film coil /l/ ('t>, (15)
) is combined with the second lower ferromagnetic thin film (13a) to form an outer iron type transformer core. In such an external iron type transformer, both the primary and secondary coils are wound close to each other in an electromagnetic coaxial manner, so that an extremely highly efficient transformer can be realized. Note that the second upper ferromagnetic thin film (14a) is not shown in FIG. 2a.

FIG. 3 shows a third embodiment of the invention. In this embodiment, a ferrite or other ferromagnetic substrate α mark is used as the head substrate, and the lower magnetic pole of the thin-film magnetic detection section (8) and the lower ferromagnetic body of the step-up transformer section αn are constructed from the above-mentioned ferromagnetic substrate 08. This reduces the number of manufacturing steps and reduces the steps in the pattern to facilitate manufacturing.

In this case, the first and second thin film coils (7), α9, and the first and second upper ferromagnetic bodies (5), (14a)
The arrangement, shape, etc. are the same as in the embodiment shown in FIG.

In addition, the nine non-magnetic materials C1 shown in the figure! J is at least the ferromagnetic substrate α&under the part where the second thin film coil/l/■ is arranged.
The second magnetic path (161
This prevents a decrease in transformer efficiency due to the elongation of the transformer.

FIG. 4 shows a fourth embodiment of the present invention. In this embodiment, the head substrate is made of ferromagnetic material such as ferrite (
A composite substrate is used in which a non-magnetic material (211) is provided at the front end of a non-magnetic material (211). Second
A magnetic detection section (8) similar to that of the embodiment is constructed, and a step-up transformer section (t71) similar to that of the third embodiment is arranged on top of the ferromagnetic material (2). Road (161
The lower part of the ferromagnetic material (2) is made of the ferromagnetic material (2). In addition,
Similar to FIG. 3, FIG. 4 illustrates a groove filled with a non-magnetic material α9 to increase transformer efficiency. This configuration prevents the first magnetic path (9) and the second magnetic path (1θ) from interfering with each other when the head is further miniaturized. ■ and non-magnetic CD
There is a method of joining a ferromagnetic material (201), a method of forming a groove in a ferromagnetic material (201), and filling it with a non-magnetic material (211). The same effect can be obtained by forming a groove filled with a non-magnetic material in the ferromagnetic substrate α mark between the cranes, or by completely separating the ferromagnetic substrate a& with a non-magnetic material. be.

In the above embodiments, the upper ferromagnetic material of the step-up transformer section αD has been described as a ferromagnetic thin film, but it may also be constructed by bonding microfabricated ferrite blocks or other ferromagnetic material blocks.

In the case of the thin film magnetic head of the present invention, the shorter the gap length, the more remarkable the effect becomes relative to the conventional head. In other words, bulkheads can be used to some extent for gap lengths up to about 0.2 μm, but for shorter gap lengths, especially extremely short gap lengths of 0°15 μm or less, it is difficult to form gaps with high precision due to manufacturing methods. becomes difficult and efficiency drops rapidly. In contrast, in the thin-film magnetic head of the present invention, the ferromagnetic thin film that constitutes the magnetic pole and the non-magnetic thin film that forms the gap are laminated using thin film forming techniques such as vapor deposition and sputtering, so even the minute dimensions described above can be achieved with precision. There is no problem whatsoever. In addition, since the magnetic path as a ring head is made as small as possible, the drop in efficiency due to narrowing the gap is extremely small, and the transformer efficiency of the step-up section is sufficiently high for practical purposes, exceeding 90%. Therefore, even signals with extremely short wavelengths can be efficiently reproduced.

As a result, even in the case of an extremely narrow gap length, the efficiency per turn is high, and the number of signal windings is increased in terms of an equivalent circuit, so sufficient absolute output can be obtained, and therefore high density signal magnetization can be carried out with high efficiency. A thin film magnetic head that can reproduce data can be realized. Its configuration is easy to manufacture;
In particular, it can sufficiently respond to the improvement in precision required as gaps become narrower, and the effect on mass production is also extremely large.

[Brief explanation of drawings]

FIG. 1a is a plan view of a thin film magnetic head according to a first embodiment of the present invention, and FIG. FIGS. 3 and 4 are cross-sectional views of thin-film magnetic heads according to third and fourth embodiments of the present invention, respectively, and FIG. FIG. 6 is a plan view of a pulse type ring head and a cross-sectional view of a conventional thin film magnetic head. (1)...Head substrate (6)...Nonmagnetic thin film (7)...First thin film coil (9)...First magnetic path ■... ...Second thin film coil α0...Second magnetic path

Claims (6)

[Claims] (1) A head substrate having a thin film forming surface substantially perpendicular to the recording medium facing surface, and a magnetic gap made of a nonmagnetic thin film aligned with the facing surface, and at least one magnetic pole is a ferromagnetic thin film. , interlinking with a first magnetic path composed of a substantially ring-shaped thin-film laminated magnetic detection section whose magnetic pole is thicker than the non-magnetic thin film, and the ring-shaped thin-film magnetic detection section and a recording medium; A first thin film coil that forms a closed circuit by itself, a thin film laminated second magnetic path made of an upper and lower ferromagnetic material that interlinks with the first thin film coil, and the second magnetic path. A thin film magnetic head comprising: a second thin film coil that is interlinked and wound more times than the first thin film coil, and output is extracted from the second thin film coil. (2) A thin film magnetic head according to claim (1), wherein the second magnetic path includes a ferromagnetic thin film. (3) The center part of the second thin film coil is located inside the closed circuit of the first thin film coil, and the upper ferromagnetic material constituting the second magnetic path connects almost the entire second thin film coil to the first thin film coil. A part of the thin film coil is covered, and the outer regions of the first and second thin film coils are coupled to the lower ferromagnetic body at the center, forming a second magnetic path as an outer iron type transformer core. A thin film magnetic head according to claim (1) or (2). (4) The head substrate is a ferromagnetic substrate, and one magnetic pole of the magnetic detection section and the lower ferromagnetic body of the second magnetic path are constructed of the ferromagnetic substrate. 1
The thin film magnetic head according to any one of items ) to (3). (5) The head substrate is a composite substrate of a ferromagnetic material and a non-magnetic material, and a magnetic detection section is arranged on the non-magnetic material part, a second magnetic path is arranged on the ferromagnetic material part, and a second magnetic path is arranged on the ferromagnetic material part. The thin film magnetic head according to any one of claims (1) to (3), characterized in that a lower ferromagnetic material of the magnetic path is formed of the ferromagnetic substrate. (6) At least the second magnetic substrate of the ferromagnetic substrate constituting the second magnetic path
Claims (4) to 3 include a groove filled with a non-magnetic material at a position where the thin film coil is arranged.
The thin film magnetic head according to any one of item (5).