JPS6348606A - magnetic head - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic transducer, that is, a magnetic head, for magnetic recording and reproduction, and particularly to a thin film video head for a VTR that performs broadband recording and reproduction.

C) Prior art) Conventionally, ferromagnetic alloy multilayer 14. Film type heads are made by depositing ferromagnetic [raw gold thin films and electrically insulating films alternately by sputtering or vapor deposition, etc. A multilayer film was formed by depositing the multilayer film, which was used as the core material. In addition, the same type of substrate was used as a temporary structure to create a sandwich structure. These strong 6n alloy multilayer thin film heads are described, for example, in the following documents.

Shibatani et al. “Manufacturing of magnetic alloy film by sputtering and its application to narrow track video head” Journal of the Institute of Electronics and Communication Engineers 57C-9 (p3”5) (1972), Haka Yono “Sendust video head for metal tape” Proceedings of the National Conference of the Society of Television Engineers 8-3 (p197) (1982), Illustrated et al. "Sputter Amorphous Video Head" Proceedings of the National Conference of the Institute of Electronics and Communication Engineers 239 (Ill-241)
(1982), H. Saito, "Fe-Al-5i alloy sputtered film video head," Japan Society of Applied Magnetics, Academic Conference Abstracts, 29P8-2 (p288) (1980).

In the configuration of such a magnetic head, ■ The core main magnetic path is composed only of a multilayer thin film of ferromagnetic alloy,
Its cross-sectional width is the same as the film thickness and is extremely narrow. Furthermore, in terms of production technology, if a misalignment occurs in the butting process of the rear gap, the gap becomes even narrower and intermittent, reducing the magnetic flux transmission efficiency. Figure 4 shows the situation. In the figure, l is the substrate, 1' is the backing substrate, 2 is the ferromagnetic alloy multilayer film part,
3 is the rear gap. Since the substrate 1 and the backing substrate BI are made of non-magnetic materials, if the films are misaligned at the rear gap portion, the magnetic flux transmission efficiency will be reduced by that amount.

■ Since the ferromagnetic alloy multilayer film and both substrates are different materials, when they slide against the magnetic tape, uneven wear occurs due to differences in wear characteristics (steps due to differences in wear).

Generally, since a high hardness and wear-resistant material is used for the substrate 1.1', a depression 2A is formed in the ferromagnetic alloy multilayer film 2 constituting the main 6n path as shown in FIG. The distance between them increases, increasing space loss and at the same time making the contact unstable.

■ Also, since this ferromagnetic alloy multilayer thin film and the substrate for thin film attachment are different materials, strictly speaking, their physical properties such as coefficient of thermal expansion do not match, and the adhesion strength during processes such as sputtering and vapor deposition is weak. . Furthermore, machining, gap forming welding,
Heat treatment or handling during the head manufacturing process often causes damage such as cracks and chips to the thin film, and even causes the thin film to break or fall off.

There were problems in terms of performance and production technology.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional drawbacks, namely, a decrease in magnetic flux transmission efficiency due to misalignment of the rear gap, an increase in space loss due to uneven wear of the head, unstable contact, and ferromagnetic alloys. The object of the present invention is to provide a magnetic head that solves problems such as the weak adhesion strength of a multilayer film to a substrate, improves recording and reproducing characteristics, especially sensitivity, and has excellent productivity.

[Means for solving problems]

In order to achieve such an object, the magnetic head of the present invention uses a ferromagnetic alloy multilayer thin film as a core material, in which the substrate is a ferromagnetic alloy base material for forming a ferromagnetic alloy multilayer thin film, or a ferromagnetic alloy base material. It is characterized by being made of a ferromagnetic alloy that has the same or almost the same wear characteristics and coefficient of thermal expansion as the material.

(Function) According to the present invention, since the core main magnetic path is made of a strong bTi alloy multilayer thin film and a ferromagnetic alloy used as its substrate, its cross-sectional width can be increased. Furthermore, even if there is a misalignment in the butting process of the rear gap portion, since the width of the main magnetic path is wide, there will be no discontinuity, and the magnetic flux transmission efficiency will not deteriorate. Furthermore, since the ferromagnetic alloy multilayer thin film and both substrates are made of the same or similar materials, when they slide against the magnetic tape, their abrasion characteristics are the same and uneven wear does not occur. Therefore, no dents occur in the ferromagnetic alloy multilayer thin film, and the head and tape operate with no space loss, ie, with good contact between the head and the tape. Furthermore, the physical properties such as the coefficient of thermal expansion are almost the same,
Strong adhesion strength during processes such as sputtering and vapor deposition.

Therefore, it is less likely to be damaged during the head manufacturing process.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

A perspective view of the first embodiment is shown in FIG. The substrate 11 for attaching a ferromagnetic alloy multilayer thin film and the backing substrate 11' for forming a sandwich structure are the base materials of the ferromagnetic alloy multilayer thin film 12 that is attached to the substrate 11 by sputtering, vapor deposition, etc. and forms the core main magnetic path. (same material), or a similar ferromagnetic alloy with a similar composition and nearly identical thermal expansion coefficient and wear characteristics, and has a gap 13, a winding window 14, and a core 15 like a normal magnetic head. It has a structure in which windings 16 are provided on both sides. In this case, the track width is determined by the thickness of the ferromagnetic alloy multilayer thin film X2 and both substrates 11, 11.
′ thickness is added to the dimension. Such a magnetic helad core is based on, for example, a Sendust plate cut and polished to a thickness of 50 μm or a Sendust quenched ribbon (reverse 11, and on top of that, Sendust with a thickness of 5 μm or 5 μm and 5i02 with a thickness of about 0.2 μm). It is obtained by repeating sputtering or vapor deposition alternately and forming a sandwich structure using the same backing substrate 11' as the substrate 11.The number of layers of the Sendust multilayer film is determined according to the track width.The alloy of the substrate and the multilayer film It is desirable that the composition be the same, but
It doesn't matter if it's a little off. For example, an amorphous Co-4r-Nb alloy can be used as the substrate and the multilayer I1fi alloy.

FIG. 2 shows a perspective view of a second embodiment of the invention, and FIG. 3 shows a top view thereof. The wooden embodiment is a case of a high-density recording head, in which only the vicinity of the gap between the substrates 11 and 11' of the first embodiment is cut from both sides to provide a recess 17, thereby narrowing the track width t. This recess may be filled with glass or the like. The thinner the substrate 11, lX' is in the recess 17, the better.

Next, the operation of this head will be explained. When a current is passed through the winding 16, a 6n east is generated in the core 15 and is transmitted to the gear ring 13, which generates a leakage magnetic field at the tip and magnetizes the medium (
Record. Conversely, the leakage magnetic flux from the medium is calculated by the gap 1
3, is transmitted to the core 15, and the winding 16 senses it, producing a (regenerative) voltage.

(Effects of the Invention) As explained above, by adopting the head configuration of the present invention, (1) the core main 6n path is made of a ferromagnetic alloy multilayer thin film and a ferro-I+U alloy used as its substrate, and its cross-sectional width can be increased; Furthermore, even if there is a misalignment in the butting process of the rear gap portion, since the width of the main circuit is wide, there will be no interruption, and the magnetic flux transmission efficiency will not decrease.

■ Since the ferromagnetic alloy multilayer thin film and both substrates are made of the same or similar materials, when they move with the magnetic tape, their abrasion characteristics are the same and no wear occurs even once. Therefore, no dents occur in the ferromagnetic alloy multilayer thin film, and the device operates with no space loss, that is, with good contact between the head and the tape.

■ Also, since this ferromagnetic alloy multilayer thin film and the substrate for ferromagnetic alloy multilayer thin film deposition are made of the same or similar materials, their physical properties such as thermal expansion coefficients are almost the same, and during processes such as sputtering and vapor deposition, Strong adhesion strength. Therefore, it is less likely to be damaged during the head manufacturing process.

By eliminating the above-mentioned drawbacks of conventional thin-film heads in terms of performance and production technology, it is possible to improve recording and reproducing characteristics, particularly sensitivity, and productivity.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the laminated head of the present invention, FIGS. 2 and 3 are a perspective view and a top view showing the second embodiment (for high-density recording), and FIG. 4 FIG. 2 is an explanatory diagram of an interrupted 6B path due to displacement of the rear gap portion in a conventional laminated head. Fig. 5 is a sectional view illustrating the increase in space loss due to flattening wear in a conventional laminated type l\rad. ...Ferromagnetic alloy multilayer thin film, 3.13...gap, 14...winding window, 15...core, 16...winding.

Claims (1)

[Claims] In a magnetic head having a ferromagnetic alloy multilayer thin film as a core material, the substrate is a ferromagnetic alloy base material for forming the ferromagnetic alloy multilayer thin film, or has the same or almost the same wear characteristics and thermal expansion coefficient as the ferromagnetic alloy base material. A magnetic head characterized by being formed from a ferromagnetic alloy.