JPH10177703A - Magnetic head and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To largely decrease undershoot caused in a reproduced waveform of a solitary wave by constituting one core half body of a nonmagnetic material and forming a modified region or a nonmagnetic region on the surface of a metal magnetic film to be in contact with the core. SOLUTION: The metal magnetic film edge 18 is irradiated with laser light to locally increase temp. so as to decrease the transmittance in the metal magnetic film edge 18. A FeTaNCr fine crystal film used as the metal magnetic film is in an amorphous state just after sputtering, however, the film is changed into a fine crystal state by annealing at the optimum heat treatment temp. Therefore, the film is heated at a temp. higher than the optimum temp. to decrease the magnetic permeability. The laser light is focused through a lens to form a spot of 4μm length and 1μm width on the head floating face by using a mask. The spot is made coincide with the metal magnetic film edge 18 of the magnetic head so as to produce a modified region with decreased magnetic permeability by irradiation of laser.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for recording / reproducing information on / from a medium in a magnetic recording apparatus such as a magnetic disk apparatus, and more particularly to a magnetic head which realizes high recording density without causing undershoot. is there.

[0002]

2. Description of the Related Art In recent years, the recording density of magnetic recording devices has been remarkably improved, and particularly in the field of magnetic disk devices for computers, the recording density has been increasing at an annual rate of 60%. FIG.
1 shows the structure of a floating magnetic head used in a magnetic disk drive for a computer.

A flying magnetic head 1 includes a non-magnetic slider 2
The magnetic core 3 is molded and fixed with glass or the like in a slit 6 formed in the floating surface 4 of the two floating surfaces 4 and 5 of the slider 2. Magnetic core 3
FIG. 8 shows the detailed structure of FIG.

[0004] In FIG. 8, a C-shaped portion on the gap-facing surface of an I-shaped core half 10 (hereinafter referred to as I-core) on the outflow end side made of an oxide magnetic material and on the inflow end side made of an oxide magnetic material are shown. A metal magnetic film 12 is formed on an inclined surface of a core half 11 (hereinafter referred to as a C core). The I core 10 and the C core 11 are joined by a glass 14 via a gap material so as to have a magnetic gap 13. In addition, a predetermined winding is wound around the I-core 10 through the winding window 15, but is omitted in FIG. In the vicinity of the floating surface exposed portion 4a of the magnetic core, a processing groove 16 for determining the track width Tw is formed parallel to the floating surface exposed portion 4a.

[0005] With the increase in recording density, a magnetic head suitable for high-frequency operation has been demanded, and for that purpose, it is necessary to reduce the inductance of the magnetic head. That is, in a magnetic head having a large inductance, the rise time of a recording current is slow, which causes a delay in a recording magnetic field, and a bit pattern expected on a recording medium is not formed, which causes an error.

In order to solve this problem, it is necessary to reduce the inductance. As shown in FIG.
2 and a magnetic head using an I-core of the non-magnetic body 101 as a magnetic core (hereinafter referred to as an I-core non-magnetic head) has been developed. As a result, the inductance of the magnetic head was significantly reduced.

[0007] Also, with the increase in recording density, non-linear magnetization transition shift (Non Linear Transition) has been proposed.
Shift (hereinafter abbreviated as NLTS) is a problem. The NLTS is a phenomenon in which a signal to be recorded is shifted from a position to be originally recorded in recording of a digital signal. As a means for solving this, the above-described inductance reduction is also effective, but as a more effective means, there is a method for improving the gradient of the recording magnetic field.

In order to realize this, as shown in FIG. 10, in the I-core 10 of the flying magnetic head 1, a part of the oxide magnetic material on the floating surface side, that is, the tip 17 of the I-core floating surface is cut out. A floating magnetic head (hereinafter referred to as an I-core tip non-magnetic head) made of a non-magnetic material has been developed. Thereby, NLTS could be reduced.

[0009]

However, in the above-described I-core non-magnetic head and I-core tip non-magnetic head, the magnetic film exposed on the air-bearing surface on the I-core side is only a metal magnetic film. The magnetic flux concentrates on the edge of the magnetic film, causing a problem of undershoot seen in a thin film head or the like. That is, an undershoot occurs near the main peak of the isolated reproduction waveform, which affects an adjacent isolated reproduction waveform, thereby causing an error. Here, the edge portion means a portion composed of a surface on the side opposite to the gap and a surface on the floating surface side.

According to the present invention, the concentration of magnetic flux on the edge portion of the metal magnetic film functioning as a pseudo gap is reduced,
An object is to reduce undershoot in a reproduction waveform.

[0011]

[Means for Solving the Problems]

(1) The present invention relates to a metal-in-gap type magnetic head in which a pair of core halves are arranged to face each other with a magnetic gap therebetween, and a metal magnetic film is formed on an opposing portion of the core halves. The one half of the core is made of a non-magnetic material, and a cutout or a concave portion is provided on the surface of the metal magnetic film on the side in contact with the one core, thereby reducing the undershoot of the reproduced waveform.

(2) According to the present invention, in the magnetic head of (1), at least a portion of the one half of the core exposed at the air bearing surface is a non-magnetic material, and the remaining portion is a magnetic material.

(3) According to the present invention, in the magnetic head according to (1), at least a portion of the one core half that is exposed to the floating surface of the one core is removed by using the half core as a magnetic material.

(4) The present invention provides (1), (2) and (3)
In any one of the magnetic heads, instead of providing the notch or the concave portion, an altered region or a nonmagnetic region having a lower magnetic permeability than the metal magnetic film is provided.

(5) The present invention provides (1), (2), (3),
In any one of the magnetic heads of (4), there is at least one of the notch or the concave portion, the altered region or the non-magnetic region, and the sum of the lengths in the track width direction is defined as 70% of the track width. % Or more and 10
0% or less.

(6) The present invention provides (1), (2), (3),
(4) using a laser device and a mask that defines a region to be irradiated by the laser device to form the notch or the concave portion or the altered region or the nonmagnetic region according to any of the above. Laser irradiation is performed on the metal magnetic film.

Here, the operation of the present invention will be described below. The magnetic flux concentrates on the edge of the metal magnetic film on the side opposite to the gap because the magnetic permeability changes suddenly at the boundary between the metal magnetic film and the I core. In order to alleviate this sudden change, a structure is provided near the boundary where the metal magnetic film and a portion having a lower magnetic permeability than the metal magnetic film overlap when viewed from the air bearing surface side. Therefore, by removing the edge portion of the metal magnetic film or decreasing the magnetic permeability of the edge portion, the change in the magnetic permeability is moderated, and the undershoot in the reproduced waveform can be reduced. Also, the portion having a lower magnetic permeability than the metal magnetic film does not necessarily need to be a part of the metal magnetic film,
A form that is part of the I core and protrudes toward the metal magnetic film may be used.

Further, in the present invention, a laser is used to form the low magnetic permeability region or the concave portion. By irradiating the laser to the edge of the metal magnetic film, the temperature of the edge of the metal magnetic film locally rises. Therefore, the metal magnetic film is locally deteriorated or partially removed by a laser. Therefore, the magnetic permeability of the edge portion of the metal magnetic film can be made lower than that of the portion not irradiated with the laser, or can be made completely non-magnetic.

Therefore, at the time of reproduction, the magnetic flux does not concentrate at the edge of the metal magnetic film, which has conventionally functioned as a pseudo gap, and the undershoot in the reproduced waveform can be reduced. In addition, by using a laser, it is possible to take measures against undershoot with good productivity with an inexpensive device, and furthermore, by using a mask to define an area to be irradiated with the laser, a manufacturing process with high accuracy and good reproducibility is performed. It can be.

The altered region or the concave portion at the edge portion of the metal magnetic film is effective in reducing the undershoot even if it does not cover the entire track width. However, in such a case, the length in the track width direction of the altered region, the non-magnetic region, the notch, or the recess at the edge of the metal magnetic film is 70% or more of the track width and 100%.
% Is desirable. Thereby, the function as a pseudo gap at the edge of the metal magnetic film can be significantly reduced, and undershoot can be reduced.

In the case where a plurality of altered regions or concave portions are provided, the total length of the plurality of altered regions or concave portions in the track width direction is 70% or more and 100% or more.
% Or less.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments. As a first embodiment, FIG. 1 shows a structure near a gap in an I-core non-magnetic head of the present invention. In the I-core of the metal magnetic film 12 and the non-magnetic material 101, an altered region or a non-magnetic region is provided at the edge 18 of the metal magnetic film 12. Here, the altered region refers to a region having a magnetic permeability lower than the original magnetic permeability of the metal magnetic film 12.

The configuration of the magnetic core of the I-core non-magnetic head shown in FIG. 1 will be described with reference to FIG. FIG. 9 uses a MnZn ferrite single crystal as the oxide magnetic material of the C core 11 and crystallized glass as the non-magnetic material of the I core 101. By configuring the I core 101 with a non-magnetic material in this way, the inductance of the magnetic core can be significantly reduced. As the metal magnetic film 12, a FeTaNCr microcrystalline film is used. The thickness of the metal magnetic film 12 is 7.8 μm on the I core side,
The C core side was 5 μm. The track width Tw is 4 μm.
m.

FIG. 2 shows a solitary wave reproduction waveform of an output signal of the I-core non-magnetic head of the present invention shown in FIG. For comparison, FIG. 12 shows a solitary wave reproduction waveform of an output signal of the conventional I-core non-magnetic head shown in FIG. The measurement conditions are both
33 turns, frequency 25.4 MHz, medium coercive force 1900 Oe, medium peripheral speed 10 m / s, flying height 40 nm
It is.

Referring to FIG. 12, the main peak 20 is located at the center.
However, a small peak in the same direction (plus direction) as the main peak is observed immediately to the left. A small peak in the opposite direction (minus direction) to the main peak is recognized at a position slightly distant to the right of the main peak. This small peak in the minus direction is the undershoot 21 with respect to the central main peak.

Incidentally, the peak immediately to the left of the main peak 20 is an undershoot with respect to the adjacent main peak (minus direction). When the position where the central main peak 20 and the undershoot 21 occur is converted into a distance based on the peripheral speed of the medium, the position is 7.8 μm on the I core side from the gap 13. Matches. That is, it can be seen that the edge portion 18 of the metal magnetic film functions as a pseudo gap and generates an undershoot. On the other hand, referring to FIG. 2, undershoot is substantially eliminated by the present invention.

As a method of lowering the magnetic permeability of the metal magnetic film edge 18 shown in FIG. 1, a method of irradiating a laser to the metal magnetic film edge 18 to locally raise the temperature is used. In particular, the FeTaNCr microcrystalline film used as a metal magnetic film is in an amorphous state immediately after sputtering, but is microcrystallized by annealing this at an optimal heat treatment temperature, thereby improving soft magnetic properties, that is, improving magnetic permeability. ing. Therefore, by applying a temperature higher than the optimum temperature, the magnetic permeability is easily reduced.

[0028]

[Table 1]

In the present invention, pulse lasers shown in Table 1 are used. The laser was condensed by a lens, and a spot having a length of 4 μm and a width of 1 μm was formed on the head flying surface using a mask. Thereafter, the spot is made coincident with the edge portion 18 of the metal magnetic film of the magnetic head, and a deteriorated region having reduced magnetic permeability is formed on the edge portion 18 of the metal magnetic film as shown in FIG. 1 by irradiating a laser. I do.

As a second embodiment, FIG. 3 shows a structure near a gap in an I-core non-magnetic head of the present invention. In the I core composed of the metal magnetic film 12 and the non-magnetic material 10,
A notch or recess is provided at the edge of the metal magnetic film 12. This notch or recess has substantially the same effect as in the first embodiment, and the edge of the metal magnetic film is removed by laser irradiation as shown in FIG. That is, even when the concave portion is formed on the air bearing surface side, the effect of reducing the undershoot is recognized as in the first embodiment.

A third embodiment will be described. In the first and second embodiments, the altered region or the concave portion caused by the laser irradiation extends over the entire track width. However, as shown in FIG. is there. However, in this case, in order to obtain the same effect as in the first and second embodiments, the length a at the edge portion of the metal magnetic film such as the altered region or the concave portion occupies 70% or more of the track width Tw. It is necessary.

The fourth and fifth embodiments will be described.
By changing the mask, laser irradiation to the regions shown in FIGS. 5 and 6 becomes possible. In this case, the sum a of the lengths at the edge portions of the metal magnetic film such as the altered region or the concave portion is:
By occupying 70% or more of the track width Tw, undershoot is greatly reduced.

Further, by providing the structure near the gap shown in the above embodiment in the non-magnetic head at the tip of the I-core shown in FIG. 10, undershoot is greatly reduced.

[0034]

As will be apparent from the above description, in a metal-in-gap type magnetic head, a region or a recess or the like which is deteriorated by laser irradiation is provided near the edge of the non-magnetic material side of the metal magnetic film. Its permeability can be sufficiently reduced or made non-magnetic, reducing the inductance and NLTS without causing undershoot in the solitary wave reproduction waveform, and at the same time, high recording density and high transfer rate It is possible to provide a magnetic head suitable for a small-sized magnetic disk device used in the present invention.

[Brief description of the drawings]

FIG. 1 is a plan view and a cross-sectional view of a magnetic head showing a first embodiment according to the present invention in the vicinity of a gap.

FIG. 2 is an oscilloscope waveform showing a solitary wave reproduction waveform of an output signal of a magnetic head according to a first embodiment of the present invention;

FIG. 3 is a plan view and a cross-sectional view of the vicinity of a gap of a magnetic head according to a second embodiment of the present invention.

FIG. 4 is a plan view and a sectional view showing the vicinity of a gap according to a third embodiment of the present invention.

FIG. 5 is a plan view showing the vicinity of a gap according to a fourth embodiment of the present invention.

FIG. 6 is a plan view showing the vicinity of a gap according to a fifth embodiment of the present invention.

FIG. 7 is a perspective view of a conventional floating magnetic head.

FIG. 8 is a perspective view of a conventional floating magnetic head.

FIG. 9 is a perspective view of a conventional I-core non-magnetic head.

FIG. 10 is a perspective view of a conventional I-core non-magnetic head.

FIG. 11 is a plan view and a sectional view showing the vicinity of a gap of a conventional I-core non-magnetic head.

FIG. 12 is an oscilloscope waveform showing a solitary wave reproduction waveform of an output signal of a conventional I-core non-magnetic head.

[Explanation of symbols]

 Reference Signs List 1 floating magnetic head, 2 slider, 3 magnetic core, 45 floating surface, 4a floating surface exposed portion of magnetic core, 6 slit, 10 I core, 11 C core, 12 metal magnetic film, 13 gap, 14 glass, 15 Winding window, 16 Track width determining groove, 17 I core floating surface tip, 18 I core side metal magnetic film edge, 20 main peak, 21 undershoot 101 Nonmagnetic I core

Claims (6)

[Claims] 1. A metal-in-gap type magnetic head in which a pair of core halves are arranged to face each other with a magnetic gap therebetween, and a metal magnetic film is formed on an opposing portion of the core halves. A magnetic head, characterized in that one half of a core is made of a non-magnetic material, and the metal magnetic film has a cutout or a concave portion on a surface in contact with the one core. 2. The magnetic head according to claim 1, wherein at least a portion of the one half of the core that is exposed to the air bearing surface is a non-magnetic material, and a remaining portion is a magnetic material. 3. The magnetic head according to claim 1, wherein the one core half is made of a magnetic material, and at least a portion of the one core exposed on the air bearing surface is removed. 4. The magnetic head according to claim 1, wherein an altered region or a non-magnetic region having a lower magnetic permeability than the metal magnetic film is provided instead of providing the notch or the concave portion. A magnetic head, characterized in that: 5. The notch according to claim 1, wherein the notch or the concave portion according to claim 1, or the altered region or the non-magnetic region according to claim 4 is at least one. Alternatively, a total sum of lengths in the track width direction of the concave portion, the altered region, or the nonmagnetic region is 70% or more and 100% or less of the track width. 6. A magnetic head according to claim 1, wherein said notch, said concave portion, said altered region or said non-magnetic region is formed by a laser device. And a method for irradiating the metal magnetic film with a laser using a mask that defines an area to be irradiated by the laser device.