JPH09161233A - Magnetic head, testing method and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate a large coil for generating magnetic field and to effectively impart the magnetic field to a magneto resistance element by generating magnetic field by a magnetic head itself. SOLUTION: A connecting part 23 is provided on one end of magnetic shields 2, 3, electrodes 201, 301 are provided on the other end and a current I for generating magnetic field is made to flow through them. The magnetic field in accordance with the current is generated in a magneto resistance element and measurement of magnetic resistance and control of magnetic domain are performed. At the time of measurement, by generating magnetic field between the magnetic shields causing a current to flow between the electrodes 201, 301 and controlling temp. by heat treatment, the heat treatment of the magneto resistance element is performed in the magnetic field. An insulation resistance between electrodes 201, 301 and the electrodes 101, 102 of the magneto resistance element or the electrodes 501, 502 of a write coil is measured. By measuring capacitance between the electrode 201 and a recording medium, a distance between a magnetic head and the recording medium is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a hard disk drive (HDD) device, a method for testing the same, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in the manufacturing process of a magnetic head,
The measurement of magnetic properties and the control of magnetic domains in magnetic materials have been performed by placing a magnetoresistive (MR) element that constitutes a magnetic head in an apparatus in which a magnetic field is uniformly generated by a coil that is larger than the outside.

2A and 2B are explanatory views of a conventional example of a magnetic head. 2 (A) is a sectional view and FIG. 2 (B) is a plan view. In the figure, 1 is a magnetoresistive (MR) element, 2 is a lower magnetic shield, 3 is an upper magnetic shield, 4 is a write pole for writing, 5 is a write coil, 101 and 102 are terminals (electrodes) of the magnetoresistive element. , 501 and 502 are terminals of the light coil.

[0004]

As shown in FIG. 2, magnetic shields sandwiching a magnetoresistive effect (MR) element 1 are provided.
It is extremely difficult to give an effective magnetic field to the magnetoresistive effect element from the outside due to the existence of the.

The present invention eliminates the need for a large coil for generating a magnetic field, which has been conventionally used for applying an external magnetic field, in a magnetic characteristic test of a magnetoresistive effect element, and effectively applies a magnetic field to the magnetoresistive effect element. With the goal.

[0006]

Means for Solving the Problems To solve the above problems, 1) a magnetoresistive effect element sandwiched between a pair of magnetic shield films is formed, and the magnetic shield films are made of a conductive material, and one ends of each are connected. , A magnetic head having electrodes on the other end thereof, or 2) a magnetic field for measuring the magnetic characteristics of the magnetoresistive element by passing a current between the electrodes to generate a magnetic field between the magnetic shield films. Head testing method, or 3) Method for manufacturing magnetic head, in which heat is applied to the magnetoresistive effect element while applying a current between the electrodes to generate a magnetic field between the magnetic shield films, or 4) Method for manufacturing the magnetic head. A method for testing a magnetic head in which the distance between the magnetic head and the recording medium is detected by measuring the capacitance between them, or 5) A current for a bias magnetic field is passed between the electrodes. Is achieved by the magnetic head is characterized in that play.

Next, the operation of the present invention will be described. In the present invention, since the magnetic head itself generates a magnetic field, (1) the magnetic characteristics of the magnetoresistive effect element can be tested without applying a magnetic field from the outside. Therefore, it is not necessary to avoid the coil for applying an external magnetic field during probing during the test, and a general prober can be used. (2) In addition, since the inspection can be performed during the manufacturing process, the processing and assembly yield after the wafer process can be improved. (3) Furthermore, it becomes possible to anneal in a magnetic field when controlling the magnetic domains of the magnetoresistive effect element.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a magnetic head of the present invention will be described with reference to the drawings. 1A and 1B are explanatory views of the embodiment.

FIG. 1A is a sectional view and FIG. 1B is a plan view. In the figure, 1 is a magnetoresistive (MR) element, 2 is a lower magnetic shield, 3 is an upper magnetic shield, 4 is a write pole for writing, 5 is a write coil, 23 is a connection part between upper and lower magnetic shields, 101, 102. Are terminals (electrodes) of the magnetoresistive effect element, 501 and 502 are terminals of the write coil, and 201 and 301 are terminals for flowing the magnetic field generating current according to the present invention to the upper and lower magnetic shields.

A general magnetic head has a magnetoresistive effect element between the upper and lower magnetic shields. In this state, since the magnetoresistive effect element is magnetically shielded by the magnetic shield, the magnetic characteristics of the magnetoresistive effect element cannot be measured. Also, a strong external magnetic field is required when performing heat treatment in a magnetic field for controlling the magnetic domains of the magnetoresistive element.

Therefore, in the present invention, the magnetic shield 2, 3
A connecting portion 23 is provided at one end of the electrode and electrodes 201 and 301 are provided at the other end so that a magnetic field generating current I flows as shown in the figure.
A magnetic field corresponding to this current is generated in the magnetoresistive element,
It is possible to measure magnetic resistance and control magnetic domains.

Considering a simple model, for example, assuming an infinitely long straight line current flowing in the upper and lower conductors in opposite directions across the gap, and assuming that the diameter of the upper and lower conductors is a and the gap is t, it occurs in the gap. The magnetic field H to be applied is represented by H = 2I / 2πr. Here, r = (a + t) / 2.

Substituting a = 2 μm and t = 0.4 μm into this equation gives H / I = 3.3 Oe / mA. Since a magnetic shield can pass a current of several 100 mA, a strong magnetic field can be generated.

Next, various measuring methods that can be carried out using the electrode of the present invention will be described. (1) A current is made to flow between the electrodes 201 and 301 to generate a magnetic field between the magnetic shields, and from the outside, for example 200 to 300 ℃
It is possible to perform the heat treatment in the magnetic field of the magnetoresistive effect element by performing the heat treatment for 1 hour and controlling the temperature. (2) Electrodes 201 and 301, and other electrodes, that is, electrodes 101 and 102 of the magnetoresistive effect element or electrodes 50 of the write coil.
Insulation resistance between 1, 502 can be measured. (3) By measuring the electrostatic capacitance between the electrode 201 and the recording medium (disk), the distance between the magnetic head and the recording medium can be detected. (4) At the time of reproducing the recording, by applying a bias magnetic field by applying a current between the electrodes 201 and 301, the read signal
It is possible to raise the S / N ratio and improve the playback characteristics.

[0015]

According to the present invention, when a magnetic characteristic test or magnetic domain control of a magnetoresistive effect element, a large coil conventionally used for applying an external magnetic field is not required, and the magnetic field is effectively applied to the magnetoresistive effect element. You can give As a result, the magnetic characteristics during the manufacturing process can be measured, and the yield can be improved. In addition, the distance between the magnetic head and the recording medium can be detected, and a bias magnetic field can be easily applied to the head to improve the reproduction characteristics.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 Magnetoresistive (MR) element 2 Lower magnetic shield 3 Upper magnetic shield 4 Write pole 5 Write coil 23 Connection part of upper and lower magnetic shields 101, 102 Magnetoresistive element terminal (electrode), 501, 502 Light coil terminal 201 , 301 Terminal for passing current for magnetic field generation to upper and lower magnetic shields

Claims (5)

[Claims] 1. A magnetoresistive effect element sandwiched between a pair of magnetic shield films, wherein the magnetic shield film is made of a conductive material, one end of each is connected, and an electrode is provided at each of the other ends. The magnetic head is characterized by 2. A method of testing a magnetic head, wherein a current is passed between the electrodes to generate a magnetic field between the magnetic shield films, and the magnetic characteristics of the magnetoresistive effect element are measured. 3. A method of manufacturing a magnetic head, wherein the magnetoresistive effect element is heat-treated while applying a current between the electrodes to generate a magnetic field between the magnetic shield films. 4. A method of testing a magnetic head, wherein the distance between the magnetic head and the recording medium is detected by measuring the electrostatic capacitance between the electrode and the recording medium. 5. A magnetic head for reproducing while applying a bias magnetic field current between the electrodes.