JPH05225528A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide the structure of a head preventing the electrical damage of the head due to the contact between a magneto-resistance effect type head and a disk. CONSTITUTION:A magneto-resistance effect element 8 and magnetic shield layers 2 and 3 around the element 8 are electrically connected, and the tip of the magneto-resistance effect element 8 is recessed from the tips of the magnetic shield layers 2 and 3. Consequently, since electric current flows through the magnetic layers previous to the magneto-resistance effect element when the head comes into contact with the disk, the element is prevent from damaging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing device.

[0002]

2. Description of the Related Art A magnetoresistive head is operated by passing a current through an element. Therefore, when the head comes into contact with the disk, an excessive current may flow through the disk, which may damage the element. As a means for preventing this, a circuit for preventing overcurrent is known, as disclosed in Japanese Patent Laid-Open No. 2-94103. Further, in order to prevent corrosion caused by contact with the human body in the consumer magnetoresistive head, as described in Japanese Patent Publication No. 2-50525, a conductive substrate is placed near the element to ground the human body. A method of applying a reverse potential is known.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
Since the protection circuit is required in addition to the normal reproduction circuit, the circuit configuration is complicated.

[0004]

According to the present invention, the tip of the magnetoresistive effect element, which is electrically connected to the magnetoresistive effect element and a magnetic shield provided close to the magnetoresistive effect element, and which is exposed on the air bearing surface side, Withdraw more than the tip of the magnetic shield.

[0005]

When the head and the medium come into contact with each other, the magnetic shield and the medium come into contact with each other before the magnetoresistive effect element comes into contact with the medium. Therefore, a current flows through the magnetic shield, and an overcurrent flows through the magnetoresistive effect element. Will not be damaged.

[0006]

EXAMPLE A first example of the present invention will be described with reference to FIG. This figure is a cross-sectional view of the magnetoresistive head as seen from the track width direction. A slider base 1 for supporting the magnetic head, two magnetic shield layers 2, 3 made of a soft magnetic film,
A first insulating layer 4 provided between the shield layer and the base, second insulating layers 5 and 6 sandwiched between the magnetic shield layers 2 and 3, and a magnetoresistive effect element sandwiched between the insulating layers 5 and 6. 8 and a third insulating layer 7 provided as a head protection film. Normally, an inductive thin film head for recording is further laminated on this protective film, but it is omitted in the figure.

Although alumina titanium carbide is used for the slider base 1, another material may be used as long as it is a material normally used for sliders. 81Ni-19Fe permalloy was used for the shield layers 2 and 3 and the magnetoresistive effect element 8. The thickness of the shield layers 2 and 3 is 1.5
The thickness of the magnetoresistive effect element 8 is 20 nm. The bias magnetic field required for the operation of the magnetoresistive effect element 8 is Nb with a film thickness of 30 nm provided in contact with the magnetoresistive effect film.
It is applied using a conductor (not shown) made of.

Alumina containing 45 wt% of silicon oxide was used for the first insulating layer 4 and the third insulating layer 7. The film thickness is 8 μm and 10 μm, respectively. Alumina containing 25 wt% of silicon oxide was used for the second insulating layers 5 and 6. The film thickness is 0.15 μm in each case. Although not shown in the figure, one end of the magnetoresistive effect element terminal is electrically connected to the magnetic shield layer on the inflow end side.

After cutting the head element, the air bearing surface is polished. Polishing was carried out by using a lapping solution containing diamond abrasive grains that is usually used and adjusting the pH to about 4. Although polishing progresses mechanochemically, the tip of the air bearing surface is slightly retracted in the shield layers 2 and 3 and the magnetoresistive layer 8 as compared with the insulating layer due to the difference in hardness. Further, comparing the shield layers 2 and 3 with the magnetoresistive effect element 8, the magnetoresistive effect element 8 is slightly retracted. This is because the second insulating layers 5 and 6 have a higher chemical etching rate than the first and third insulating layers 4 and 7. In this way, the amount of retraction can be controlled by changing the lapping speed of the insulating layer sandwiching the magnetoresistive effect element and the lapping speed of the surrounding insulating layer. The average amount of retraction in this example is about 5 nm in the shield layer and 7 n in the magnetoresistive element with respect to the positions of the first and third insulating layers.
I'm withdrawn.

When the frequency of head damage due to contact is investigated using a head in which the tip of such a magnetoresistive effect element is retracted from the tip of the magnetic shield layer, it is generated as compared with the conventional head having the same tip. The frequency could be reduced to about 20%.

In the above examples, the case where the content of silicon oxide was changed in order to change the lapping rate of the insulating layer was shown. However, the same effect can be obtained by adding zirconium oxide or tantalum oxide. The lapping speed can be increased by reducing the additive.

[0012]

According to the present invention, it is possible to prevent the magnetoresistive effect element from being damaged by the electrical contact between the head and the disk.

[Brief description of drawings]

FIG. 1 is a sectional view of a head showing an embodiment of the present invention.

[Explanation of symbols]

1 ... Slider substrate, 2, 3 ... Shield layer, 4 ... First insulating layer, 5, 6 ... Second insulating layer, 7 ... Third insulating layer, 8 ... Magnetoresistive effect element.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Kitada 1-280, Higashi Koigokubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (2)

[Claims] 1. A magnetic recording device having a magnetoresistive head in which a ferromagnetic thin film having a magnetoresistive effect is sandwiched by a soft magnetic material with an insulating layer interposed between the magnetic shield layer exposed on the medium surface and the medium. A magnetic recording / reproducing apparatus characterized in that a distance between the ferromagnetic thin film and the medium is larger than a distance. 2. A magnetic head using a magnetic head according to claim 1, wherein an insulating layer sandwiching the magnetoresistive element provided inside the magnetic shield layer and an insulating layer other than the insulating layer have different material compositions. Recording / playback device.