JPS6331015A - thin film 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 a magnetic head, and particularly to a thin film magnetic head suitable for UTR and the like.

[Conventional technology]

An example of a conventional thin film magnetic head is JP-A-55-840.
There is a thin film magnetic head described in Japanese Patent No. 19. In this magnetic head, the width of the yoke structure is gradually increased behind the magnetic pole tip region, and the thickness of the magnetic layer is approximately 6 mm.
It has increased by 0X. This makes York #! It counters the saturation of J-build construction and is highly efficient.

[Problem that the invention seeks to solve]

However, in general, no consideration is given to the output per unit inductance in consideration of magnetic velocity leakage, and this point is not taken into consideration in the above invention either.

Further, in the conventional example, no consideration has been given to the width of the magnetic layer forming the yoke structure. As the width of the magnetic layer increases, the efficiency of the magnetic head increases, but at the same time leakage between the upper and lower magnetic layers increases, and inductance also increases. Normally, the performance of a magnetic head requires reproduction output at a certain inductance, so if the width of the magnetic layer is made larger than necessary, the inductance will become too large. It is necessary to reduce the number of turns, and as a result, there is a problem that an improvement in output per unit inductance cannot be expected.

Furthermore, the conventional example does not mention the inclination angle of the sloped portion from the front actuation bayup forming portion to the upper part of the signal coil, and the spacing between the upper and lower magnetic layers.

Magnetic leakage varies greatly depending on the angle of inclination and spacing, and unless the shape is optimized, the inductance increases and the output decreases due to the glue cage in that part, resulting in no improvement in performance.

[Means for solving problems]

An object of the present invention is to provide a magnetic core shape that maximizes the output per unit inductance.

In order to achieve the above object, we focused on the fact that the reproduction efficiency and inductance of a magnetic head are determined by the magnetic resistance of the magnetic core and the magnetic flux leakage between the magnetic cores, and searched for an optimal shape.

The present invention includes a lower magnetic core formed on a non-magnetic substrate,
A magnetic core consisting of an upper magnetic core formed through a gap spacer material, a signal coil, an insulating material, etc., an operating gap formed by a gap spacer material at the connection part of the upper and lower magnetic cores, and a signal coil for signal detection. In the magnetic head, at least part of the core width is
3 < b / a < 8 [Operation] By considering the magnetic resistance of the core and magnetic flux leakage, the inductance can be small and the efficiency can be greatly increased, so the per unit inductance output can be increased.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of the thin-belly magnetic head shown in this embodiment. The structure of the magnetic head in this example includes glass,
A magnetic film 2 formed on a non-magnetic substrate 1 such as a ceramic is used as a lower magnetic core, and a gap material 4 is formed on the lower magnetic core.
A magnetic circuit is formed by the magnetic films 2 and 3 via the signal coil 6 and the insulating material 5, using the magnetic film 3 as an upper magnetic core.

For the magnets t[2, 3, sendust, permalloy, amorphous alloy, etc. are used. In this example, Co-based Co-
A Nb-Zr alloy film was used and formed by RF sputtering.

The gap material 4 is 5i02. A non-magnetic insulating material such as At20s or a non-magnetic conductor such as Cr or Zr can be used. In this example, Cr was formed to a thickness of 03 μm by sputtering. The signal coil 6 is formed of Cu, and the surrounding area is 8.
It is surrounded by an insulating material such as 102.

FIG. 2 shows a plan view 2 of this embodiment. FIG. 2 shows the upper magnetic core 3.

From FIGS. 1 and 2, head shape parameters are set as follows. Distance t between the upper and lower cores, angle formed by the lower core and upper core at the rear end of the working gap, θ, front core width, a
l Rear core 11b However, the front core width a is equal to the track width.

- In this example, t=20μm, θ=60°, a
= 20μ"% b = 100μm. There is a relationship between these shape parameters and head performance as shown below. However, when the head performance is 5MHz output C and 4MHz inductance L, per unit inductance Evaluation was made using the output C/7LE.

Figure 3 shows the ratio of front core width to core width, b/a and C/
Indicates the relationship between y'L. The maximum value is b/az5. If the allowable value is -0.5dB from the maximum value, 3≦b
/ a≦8. The reason why C/(L takes the maximum value 2 in this way is that the changes in C and L with respect to winter are different. In other words, in the region where winter is small, efficiency is low, and because C is small, C
In the region where /y'L is small and b/a is large, the efficiency approaches saturation, but since L continues to increase uniformly, C/y'
L decreases.

FIG. 4 shows the change in C/F'L with respect to θ. θ=π/
2 is the maximum value, and it will not change any further up to π. Also, if the allowable value is -0.5 dB, π θ≦.

Figure 5 shows the ratio of front core width to upper and lower coil spacing L/
The relationship between a and output C/rL is shown. If the maximum value is taken at a CCt and the allowable value is -0.5dB, then 0.5'-≦
It is 25.

In the present invention, the allowable output value is set to the maximum value -0.5 dB. This is the limit within which a reduction in output does not cause problems with product quality such as image quality.

Another embodiment of the invention is shown in FIG. A recess is provided on a non-magnetic substrate 1, a magnetic film 2 is formed, a gap material 4, an insulating material 5, and a signal coil 6 are formed, a magnetic film 3 is formed, and a magnetic core is formed by the magnetic films 2 and 6. .

α is the lower angle between the operating bayup surface and the inclined surface of the upper magnetic core.
1. If the T angle of the lower magnetic core is α2, then α1+
α2 corresponds to θ in the above embodiment.

In this example, α1+α2≧π/4, and α1×α
It was set as 2. With such a structure, the accuracy of the upper magnetic core can be improved.

Furthermore, it is possible to obtain the inclination angle α2 by machining a concave portion in the lower magnetic core 2. With this method, it is not necessary to use a film on the sloped portion of the lower magnetic film, and the characteristics can be improved. can.

〔Effect of the invention〕

According to the present invention, the inductance is minimized by considering the magnetic resistance of the core and magnetic flux leakage.
A shape that increases efficiency can be obtained, which has the effect of increasing output per unit inductance.

[Brief explanation of the drawing]

Figure 1 is an old sectional view of a thin film magnetic head according to an embodiment of the present invention, Figure 2 is a plan view of the same, Figure 5 is a graph showing the relationship between shape and performance, and Figure 6 is a thin film magnetic head. FIG. 3 is a cross-sectional view of a magnetic head. DESCRIPTION OF SYMBOLS 1...Nonmagnetic substrate, 2...Magnetic film (lower magnetic core), 3...Magnetic film (upper magnetic core), 6...Signal coil. a! Tomoe Daifu Figure 〆θ (yo-d,) 5th Senbutsu 6th Ward

Claims (1)

[Claims] 1. A magnetic core consisting of a lower magnetic core formed on a non-magnetic substrate, an upper magnetic core formed via a gap spacer material, a signal coil, an insulating material, etc., and a gap spacer material at the connection part of the upper and lower magnetic cores. In a magnetic head consisting of a working gap formed by a working gap and a signal coil for signal detection, when the track width is a and the core width other than the working gap forming part is b, at least a part of the core width satisfies 3≦b/
A thin film magnetic head characterized in that a≦8.