JPH0554340A - Composite magnetic head - Google Patents

Abstract

PURPOSE:To accurately control the current value to be energized to a head winding at the reproduction by parallely providing resistance branching the direct current to a head winding. CONSTITUTION:The bias is impressed to an MR magnetic sensing part 5 by supplying the current from the direct power supply to a head winding 11 at the time of reproduction while omitting a bias conductor. Further, a resistance part 14 is provided parallely to the head winding 11. Therefore, at the recording of this magnetic head on a hard disk, one part of the current from the direct power supply to be supplied to the head winding 11 is branched to flow to the resistance part 14, and the optimum current value flows to the head winding part 11 at the reproduction. Therefore, the adjustment of the resistance value of the resistance part 14 parallely provided on this head winding 11 can easily optimize the supply current value to the head winding 11 at the reproduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite magnetic head suitable for recording / reproducing on / from a hard disk, for example.

[0002]

2. Description of the Related Art For example, a recording / reproducing head of a hard disk drive device comprises a recording head of an inductive head and a reproducing head of a magnetoresistive head (hereinafter referred to as an MR head) having excellent short wavelength sensitivity. It is generally a composite type.

As such a composite type magnetic head, one having a structure as shown in FIGS. 4 and 5, for example, is known. This magnetic head uses Al ₂ O fixed to a slider.
The first magnetic recording medium has a magnetic gap g between the front end of the base 51 made of _3- TiC and the like, which faces the surface facing the hard disk, that is, the ABS (air bearing surface) 52. The thin film magnetic core 53 and the second thin film magnetic core 54 are laminated with a predetermined gap. Further, one end of the magnetoresistive effect sensing portion (hereinafter referred to as MR sensing portion) 55 or at least one tip pole 56a thereof is formed of at least the magnetoresistive effect thin film (hereinafter referred to as MR thin film) in the magnetic gap g. Are arranged so as to face the ABS surface 52.

On the side opposite to the ABS surface 52, the other electrode 56b of the MR magnetic sensing section 55 is provided with the one electrode 56.
It is provided substantially parallel to a. The MR magnetism sensing portion 55 is provided with a magnetized state in a desired direction by energizing the MR magnetism sensing portion 55, and linearity with excellent magnetoresistive effect characteristics is provided. A bias conductor 57 which operates so as to operate in a characteristic region exhibiting high sensitivity is provided so as to cross the MR magnetic sensing section 55 via an insulating layer 58. And further, the thin film magnetic cores 53, 5
A spiral head winding 59 is provided so as to surround the magnetic coupling portion which is the connection portion of No. 4.

The composite type magnetic head thus formed has a first thin film magnetic core 53 and a second thin film magnetic core 54.
A so-called shield type MR head having a magnetic shield as a magnetic shield, and an inductive head having a head winding 59 wound around a magnetic path formed by the first thin film magnetic core 53 and the second thin film magnetic core 54. It has a composite type head configuration. Recording in this magnetic head is performed by the terminal portions 59a, 5 drawn from the head winding 59.
A current from an AC power supply is supplied to 9b to generate a magnetic flux based on the recorded information from a magnetic gap g facing the ABS surface 52. On the other hand, for reproduction, a current is supplied from a DC power supply to the terminal portions 60 and 61 of the front electrode 56a and the rear electrode 56b, which are stacked on the front and rear ends of the MR magnetic sensing unit 55, respectively, and a current M
This is performed by supplying a sense current to the R magnetically sensitive portion 55 and a direct current to the terminal portions 57a and 57b of the bias conductor 57 to give a magnetized state to the MR magnetically sensitive portion 55.

[0006]

However, with the above-described structure, the MR magnetic sensing section 55, the bias conductor 57, and the terminals 60, 61, 57a, 57b, 59a of the head winding 59,
Since two 59b are required, a total of six terminals are required. Such a large number of terminals is disadvantageous for a magnetic head for a hard disk, which is being miniaturized due to demands such as expansion of an effective recording area and high-speed drive of the head.

Therefore, in the prior art, the applicant of the present invention applies a bias magnetic field to the MR magnetic sensing section 55 by passing a direct current through the head winding 59 during reproduction, and uses the head winding 59 as the bias conductor 57. Attempts have been made to do so. That is, the bias conductor 57 is eliminated to reduce the number of terminals to four. In this composite type magnetic head, an AC current is passed through the head winding 59 as usual for recording, but a reproducing operation is performed by supplying a DC current to the head winding 59 instead of the bias conductor 57.
A bias magnetic field is applied to the R magnetic sensing section 55.

In this method, however, the number of turns of the head winding 59 required to generate the magnetic field required for recording is 10 or more, so that if a direct current is simply passed through the head winding 59, the bias conductor A bias magnetic field of about 10 times or more compared with the case of energizing 57 is applied to the MR magnetic sensing part 55. For example, the optimum bias when the current supplied to the bias conductor 57 is approximately 10 to 20 mA becomes optimal when it is approximately 1 mA, which makes it extremely difficult to control the current value.

Therefore, the present invention has been proposed in view of the above technical problems, and makes it possible to optimally control the bias current supplied during reproduction and to reduce the number of head terminals. An object of the present invention is to provide a composite type magnetic head that can be manufactured.

[0010]

In order to achieve the above-mentioned object, the present invention provides a first thin film which forms a recording magnetic gap between front ends facing a surface facing a magnetic recording medium. A magnetic core and a second thin film magnetic core are laminated, a magnetoresistive effect magnetic sensitive portion is arranged rearward from the contact surface in the magnetic gap, and a head winding is arranged rearward thereof. At the time of reproduction, a DC current is made to flow from the DC power supply to the head winding to apply a bias magnetic field to the magnetoresistive effect magnetic sensitive section, and a resistor for branching the DC current is provided in parallel with the head winding. It is a feature.

[0011]

In the composite magnetic head of the present invention, the bias conductor is omitted and a bias is applied to the MR magnetic sensing section by supplying a current from the DC power supply to the head winding during reproduction. A resistor is provided in parallel with the winding. Therefore, when recording to a hard disk with this magnetic head,
Part of the current from the DC power supply supplied to the head winding branches and flows to the resistance part provided in parallel with the head winding,
An optimum current value flows through the head winding during reproduction. Therefore, by adjusting the resistance value provided in parallel with the head winding, the value of the current supplied to the head winding during reproduction can be easily optimized.

Further, in the composite type magnetic head of the present invention, since the head winding is made to function also as the bias conductor, the area for disposing the bias conductor and further the terminal portion from this bias conductor are An arrangement area and the like are not required, so that the structure can be simplified and the head can be downsized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. In the composite magnetic head of the present embodiment, as shown in FIGS. 1 and 2, the first thin film magnetic core 1 and the second thin film magnetic core 2 forming the magnetic gap g between the front end portions are made of Al ₂ O ₃ -Ti
They are laminated on a base body 3 called a slider made of C or the like so as to face each other with a predetermined gap.

The first thin-film magnetic core 1 is provided directly on the base body 3, and one end of the first thin-film magnetic core 1 is made to face an ABS surface 4 which is a contact surface with a magnetic recording medium, for example, a hard disk. Is provided so as to extend in a direction substantially orthogonal to. On the other hand, the second thin-film magnetic core 2 has its one end facing the ABS surface 4
The first thin film magnetic core 1 is provided so as to extend in a direction substantially orthogonal to the surface 4 and has a front end portion facing the ABS surface 4.
It is bent and formed so that the gap between and is narrowed. A magnetic gap g, which functions as a recording gap, faces the ABS surface 4 between the front end portions where the gap is narrowed. Further, the second thin film magnetic core 2 magnetically contacts the first thin film magnetic core 1 at the rear end to form a back gap and a closed magnetic path.

In this magnetic head, an MR magnetic sensitive portion 5 which is a magnetoresistive magnetic sensitive portion is provided rearward from the ABS 4 in the magnetic gap. MR
The magnetically sensitive portion 5 is formed as a rectangular pattern slightly narrower than the track width Tw of the magnetic gap g, and is provided such that its longitudinal direction is orthogonal to the ABS surface 4. The MR magnetic sensing section 5 has ABS at its one end.
It is arranged so as to face the surface 4, and the rear edges thereof are positioned so as to reach approximately the middle portions of the first thin film magnetic core 1 and the second thin film magnetic core 2 which face each other. The MR magnetic sensing unit 5
Are provided on the first thin film magnetic core 1 via the first insulating layer 6a in order to insulate the first thin film magnetic core 1 provided on the base body 3. Also, the above M
In order to avoid the occurrence of Barkhausen noise, the R magnetic sensing section 5 may be formed by laminating a pair of MR thin films that are magnetostatically coupled via a nonmagnetic insulating layer made of, for example, SiO _2. desirable.

A pair of electrodes 7a and 7b (hereinafter, referred to as ABS surface 4 side) for passing a sense current from a constant current source (not shown) are provided at the front end and the rear end of the MR magnetic sensing unit 5. The electrode 7a is referred to as a front end electrode 7a, and the electrode 7b provided at the rear end portion is referred to as a rear end electrode 7b).

The tip electrode 7a is formed as a wiring pattern having a substantially L shape in a plan view, and one end of the wiring pattern is the MR.
The MR sensitive portion 5 is laminated on the tip of the magnetic sensitive portion 5 and
One side edge of the pattern on the upper side is exposed to the ABS surface 4. The end portion of the wiring pattern drawn to the back side is the ground side terminal portion 8.

On the other hand, the rear end electrode 7b is the front end electrode 7a.
Similar to the above, it is formed as a substantially L-shaped wiring pattern in a plane, and is provided on the side opposite to the tip electrode 7a with the MR magnetic sensing part 5 interposed therebetween. The rear end electrode 7b is laminated on the rear end of the MR magnetic sensing part 5, and the end of the wiring pattern drawn to the back side serves as the terminal part 9 on the current source side.

Behind the rear end electrode 7b, a spiral head is formed so as to surround a magnetic coupling portion 10 which is a connection portion between the first thin film magnetic core 1 and the second thin film magnetic core 2. A winding wire 11 is provided. The head winding 11 serves to supply a current according to the recording information to the magnetic path formed by the first thin film magnetic core 1 and the second thin film magnetic core 2 at the time of recording, and at the time of reproduction, the MR magnetic sensing section 5 It functions as a bias conductor that gives a magnetized state in a desired direction. The head winding 11 is embedded with a second insulating layer 6b and a third insulating layer 6c in order to ensure insulation with the electrodes 7a and 7b, the MR magnetic sensing section 5, and the second thin film magnetic core 2. Has been. And
The ends of the wiring pattern drawn from both ends of the head winding 11 serve as terminals 11a and 11b for passing a current from the DC power supply or the AC power supply supplied to the head winding 11. A protective film layer 12 is laminated on the second thin film magnetic core 2 in order to protect the composite magnetic head including the inductive head and the MR head configured as described above.

In the composite magnetic head constructed as described above, the head winding 11 is used in place of the bias conductor, and a direct current is supplied to the head winding 11 so that the MR magnetic sensing section 5 can operate. Since the bias state is not required, the number of terminals can be reduced by the amount that the bias conductor is unnecessary, and the arrangement area can be reduced, and the head can be miniaturized. Therefore, downsizing
It is suitable for a magnetic head for a hard disk that requires a large recording capacity.

In particular, in the composite magnetic head of this embodiment, as shown in the drive circuit diagram of this head in FIG. 3, a resistor for branching the current Ia from the DC power supply 13 supplied to the head winding 11 at the time of reproduction is provided. 14 is provided in parallel with the head winding 11. Therefore, the head winding 11
When a DC current Ia is supplied from the DC power supply 13 to the head winding 11, all the current Ia does not flow to the head winding 11, but a part thereof flows to the resistor 14 provided in parallel. Therefore, the controllable current value Ia is set to the AC power supply 13
By supplying more, the optimum current value Ic required at the time of reproduction can be supplied to the head winding 11. During reproduction, a sense current is supplied from the DC power supply 15 to the MR magnetic sensing section 5 to the front electrode 7a and the rear electrode 7b.

Here, for example, the resistance of the head winding 11 is set to R
c, and letting the resistance of the resistor 14 provided in parallel with the head winding 11 be Rb, the currents Ib and Ic flowing respectively are
Ib / Ic = Rc / Rb. At this time, the current value Ia of the circuit becomes Ia = Ib + Ic. If this Ia is a controllable value, the bias value applied to the head winding 11 can be optimized. Ia is 10m
Since control is easy if it is A or more, if Rc = 10Ω, the resistance 14 should be set to Rb = 1Ω. On the other hand, at the time of recording, the terminals 11a and 11b of the head winding 11 may be connected to the AC power supply 16 as in the conventional case.

[0023]

As is apparent from the above description, according to the composite magnetic head of the present invention, the resistance is provided in parallel with the head winding, so that the current supplied from the DC power source is reduced. It is possible to cause a portion to flow to the resistance portion, and to pass an optimum current value required for reproduction to the head winding. Therefore, it is possible to control the value of current flowing to the head winding during reproduction with high accuracy, and it is possible to apply a bias having an optimum value to the MR magnetic sensing section.

Further, in the composite magnetic head of the present invention, since the head winding is made to function also as the bias conductor, the area for disposing the bias conductor, and further the disposition of the terminal portion of this bias conductor. The area and the like are not required, and the structure can be simplified and the head can be downsized. Therefore, according to the composite type magnetic head of the present invention, it is extremely effective when used as a magnetic head for a hard disk which is required to be downsized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a composite magnetic head to which the present invention is applied.

FIG. 2 is a schematic plan view of the composite magnetic head of FIG.

FIG. 3 is a drive circuit diagram of the composite magnetic head of the present invention.

FIG. 4 is a sectional view showing an example of a conventional composite magnetic head.

5 is a schematic plan view of the composite magnetic head of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st thin film magnetic core 2 ... 2nd thin film magnetic core 4 ... ABS surface 5 ... MR magnetic sensing part 7a ... Front electrode 7b ... Rear electrode 11 ...・ Head winding 13 ・ ・ ・ DC power supply 14 ・ ・ ・ Resistance

Claims (1)

[Claims] 1. A first thin-film magnetic core and a second thin-film magnetic core, which form a recording magnetic gap and face a surface facing a magnetic recording medium, are laminated between the front end portions, and within the magnetic gap. The magneto-resistive effect magnetic field is placed from the contact surface of the head to the rear, and the head winding is placed behind it. A composite magnetic head, characterized in that a bias magnetic field is applied to the magnetically sensitive portion, and a resistor for branching the direct current is provided in parallel with the head winding.