JPS5977614A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain a thin film magnetic head enabled to be used at high frequency by dividing at least a part of a rear core part for forming a magnetic path by an insulating material. CONSTITUTION:An Ni-19wt% Fe alloy layer of 0.5mum thickness and an SiO2 layer of 0.1mum thickness are laminated on a non-magnetic substrate 1 consisting of a photoserum to form a lower magnetic layer 2 of 3mum thickness by a sputtering method. The lower magnetic layer 2, an upper magnetic layer 5 and a coil 3 are insulated by an insulating layer 4. The upper magnetic layer 5 is formed in the same manner as the lower magnetic layer 2 and divided by the insulating material 6 so as to have a width less than the track width. The upper and lower magnetic layers 2, 5 are connected by a connection part 7. Since the loss of eddy current is reduced by said constitution, the thin film magnetic head enabled to be used at the high frequency is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a thin film magnetic head, and particularly to a magnetic head structure with good characteristics in a frequency band.

Conventional Techniques v Toner J Conventional magnetic heads are so-called bulk heads in which magnetic poles are formed by machining and wound to form a coil. Such heads have a large stray capacitance and are difficult to use in high frequency bands, and are only used in the frequency range below ~IOMH2. A so-called thin-film magnetic head that performs magnetic inertia formation and thin-film winding ID' is being developed, but even this has the disadvantage that recording and reproducing efficiency decreases at frequencies of about 100 M)1 OBJECTS OF THE INVENTION The object of the present invention is to provide a thin film magnetic bed that can be used in high frequency waves by devising the structure of the magnetic poles.

[Summary of the invention]

The structure of the present invention for achieving the above-mentioned target sound is that at least a portion of the rear core portion for forming the magnetic path sound is separated by an insulator.

Since the present invention has the above-mentioned configuration, the width of the rear core for forming magnetic path sound is made larger than the track width for recording and reproducing, lowering the magnetic resistance and increasing the recording and reproducing efficiency. At the same time, at least part of the core portion is divided into widths smaller than the track width by an insulator, reducing vortex N1 flow loss and loss due to resonance, and can be used up to high frequencies.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. 1st
Figure (a) is a sectional view of the main part of the thin film head of the present invention, (l)
) shows a corresponding plan view of 2.5 portions of both the upper and lower magnetic layers (the AA' section in (b) corresponds to (a)).

Symbol 1 is a non-magnetic substrate, and in this example, it is a photocerano substrate (USA) with a thickness of L mm and a diameter of 40 mm.

(manufactured by Corning Inc.) was used. Symbol 2 is a lower magnetic layer, which is formed by laminating Ni-1gwt%Fe alloy with a thickness of about 0.5 μm and 5i02 with a thickness of about 0.1 μm to a total thickness of about 3 μm, and was formed by sputtering.

The lower magnetic layer, like the upper magnetic layer 5, was divided by an insulating layer. Symbol 3 is a thin film coil, which is deposited to a thickness of about 2 μm and made into a 4-turn coil using photolithography technology. Symbol 4 is an insulating layer for magnetically and electrically insulating the lower magnetic layer 2, the upper magnetic layer 5, and the 4-turn coil 3, and in this example, a stow layer with a thickness of about 1 μm formed by sputtering is used. It was formed by spin coating and a polyimide resin was used. Are these structures and head manufacturing techniques well-known? Since it can be easily formed using this method, the details will be omitted. Symbol 5 is Ni-19wt%Fe with a total thickness of about 2 μm constituting the upper magnetic layer.
A laminate of alloy and 8fO2 was formed by sputtering in the same manner as the lower magnetic layer. The magnetic layer is divided by an insulator 6 as shown in FIG. 1(b). Is this kind of division possible using photolithography technology? This is possible with the conventional technology of patterning the magnetic layer using
Since it is desirable for the characteristics to be about m, is this kind of precision processing? Is there a dry etching method such as ion milling for this purpose? It is desirable to use it. The effect is great when the width WVi of the divided magnetic layer is equal to or less than the track width Tw. Both the upper and lower magnetic layers do not necessarily have to be divided in the same way, and even if only one is divided, the effect is great. The effect is also great when a magnetic substrate of an insulating material such as Ni--Zn ferrite or Mn--Zn ferrite is used as the lower magnetic layer, and the upper magnetic layer is vigorously separated. In this example, the divided width of the magnetic layer is defined as the track width 25 μm.
It was divided into four parts by an insulating layer having a width of 2 μm so that the width was less than 2 μm. The divided insulating layers were 5i02 for the lower magnetic layer, and no filler was used for the upper magnetic layer, making it an all-air insulating layer. Note that in FIG. 1(b), the symbol 7 indicates the connecting portion (back gap) between the upper and lower magnetic layers.

FIG. 2 shows the frequency characteristics of the self-recording and reproducing output of the magnetic head of this embodiment and the conventional magnetic head (which has a structure similar to that of this embodiment except that the magnetic layer is separated). show. Is measurement affected by recording wavelength? The relative speed between the head and the medium was fully adjusted to avoid any damage.

It can be seen that characteristic 11 of the head of the present invention is better in high frequency characteristics than characteristic 12 of the conventional magnetic head.

〔Effect of the invention〕

What is the magnetic resistance of the magnetic path in a normal thin film magnetic head? Decrease recording and playback efficiency? To increase this, the width of the rear core is made larger than the track width. Also, the high frequency characteristics of the magnetic layer? Magnetic layer to make it better? It is also a known technique to form a multilayer structure with thin, insulating layers. but,
These measures alone cannot reduce eddy current loss due to capacitive coupling, and the high frequency characteristics are poor. If the present invention is applied to the configurations of these known techniques, eddy current loss can be reduced, high frequency characteristics are improved, and a head that can be used at frequencies of about 100 M) IZ can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating the entire thin film head as an embodiment of the present invention, (a) is a sectional view of the main part, (b) is a plan view of both the upper and lower magnetic layers, Figure 2 shows the frequency characteristics of the thin film head using the present invention? FIG.

Claims (1)

Claims: 1. A thin film magnetic head characterized in that at least a portion of a rear core portion for forming a magnetic path is separated by an insulator. 2. In the thin film magnetic head according to claim 1, the maximum width of the rear core is t% larger than the track width for recording and reproduction. 3. The magnetic pole of the thin film magnetic head according to claim 1 is composed of a laminate of a ferromagnetic composite and an insulating material.