JPS61908A - Magnetoresistance effect type playback head - Google Patents

Abstract

PURPOSE:To improve the quality of the output signal reproduced by a head by providing a non-hygroscopic insulating layer between a magnetic substrate having conductivity and a non-magnetic insulating layer. CONSTITUTION:Two magnetoresistance effect elements MR elements 22, 23 are provided on the magnetic substrate 21 having conductivity via the composite non-magnetic insulating layer 24 consisting of the non-magnetic insulating layer 24a having non-hygroscopicity and the non-magnetic insulation layer 24b having good smoothness on the layer surface. A magnetic material layer 26 for shielding and a cover plate 27 are further provided atop said elements via a non-magnetic insulating layer 25. The insulation resistance between the substrate 21 and the MR elements 22, 23 on the sliding contact surface of the head which contacts slidingly with a magnetic tape or recording medium 28 is thus increased. The leakage of bias current and externally induced noise fault are eliminated and the good magnetic reproduction characteristic is stably obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Field of Application The present invention relates to a magnetoresistive reproducing head used in a file device such as a magnetic tape device. This article relates to a head configuration that aims to improve insulation resistance characteristics.

A magnetic flux response type magnetic head that uses a magnetoresistive element configured to output magnetic field strength as a change in electrical resistance as a magnetic head for reproducing recorded edge information of a magnetic tape recording medium in a magnetic tape device, etc. Magnetoresistive read heads are well known, and various types have already been proposed.

(bl) Prior Art The conventional magnetoresistive reproducing head described above generally has a magnetic substrate 1 made of, for example, Ni-Zn ferrite or Mn-Zn ferrite, as shown in the cross-sectional view of the main part in FIG. , two magnetoresistive elements (hereinafter referred to as MR elements) 2.3 made of N1-Fe permalloy are provided with a non-magnetic insulating layer 4 made of 5i02 or the like interposed therebetween as shown in the figure, and Ni-Fe A shielding magnetic layer 5 made of permalloy and a cover plate 6 are laminated.

In addition, the substrate 1 also serves as a shield layer, and as described above.
The reproducing resolution of the head is improved by configuring the magnetic substrate 1 and the shielding magnetic layer 5, which are arranged to sandwich two MR elements 2.3 between them, to work as a shielding magnetic material. ing.

Therefore, in order to reproduce the recorded line information on the magnetic tape recording medium 7 facing the magnetic tape recording medium 7 using the magnetoresistive reproduction device having such a configuration, it is necessary to supply a predetermined constant current to the two MR elements 2.3. Therefore, due to the magnetic fields generated by these currents, bias magnetic fields in opposite directions are applied to the two MR elements 2.3.

At this time, the two opposing MR elements 2
．． 3, a resistance change occurs in the opposite direction, so this change in electrical resistance is converted into a voltage, and the recorded signal is detected differentially and reproduced.

(C) Problems to be Solved by the Invention Incidentally, in the conventional magnetoresistive reproducing head configured as described above, as described above, the magnetic substrate 1 and the Mllll element 2 are
Since the non-magnetic insulating layer 4 made of 5i02 is used as an interlayer insulating layer between the substrate l and M
There is a problem that the insulation resistance between the R elements 2 cannot be increased.

This problem is due to the fact that the non-magnetic insulating layer 4 made of 5i02 has hygroscopic properties, and the insulation resistance is greatly affected by atmospheric humidity or by use in a particularly humid atmosphere, resulting in a decrease in the insulation resistance. do.

For this reason, when the insulation resistance between the substrate 1 and the MR element 2 becomes low, a part of the bias current of the MR element 2.3 leaks to the substrate 1 side, and the bias characteristics shift, resulting in the waveform of the output signal. However, there are disadvantages in that the signal quality is degraded due to distortion of the signal and external induction noise mixed into the output signals of the MR elements 2 and 3 from the substrate 1 side.

Therefore, in order to eliminate such drawbacks, conductive magnetic substrate 1 and MI? We also attempted to apply a non-magnetic insulating layer made of Al2O3, which has almost no hygroscopicity, as the glabellar insulating layer between the element 2, but the Al2O3 layer is generally 3402
The smoothness of the surface of the layer is poor compared to that of the Al2O layer.
When the ferromagnetic layer that becomes the MR element 2.3 is formed directly on the 3 layers, the magnetic properties of the key element 2.3 made of the ferromagnetic layer deteriorate due to poor underlying smoothness on the surface of the Aβ203 layer. There was the inconvenience of doing so.

In view of the above-mentioned conventional drawbacks, the present invention provides Ml? The purpose of the present invention is to provide a novel magnetoresistive reproducing head that increases the insulation resistance between the magnetic substrate and the MR element without deteriorating the magnetic properties of the element, thereby improving the quality of the head reproduction output signal. It is something to do.

(dl Means for Solving the Problems) The object of the present invention is to provide a head structure in which a magnetoresistive element with a non-magnetic insulating layer interposed therebetween and a shielding magnetic layer are laminated in this order on a conductive magnetic substrate. This is achieved by the magnetoresistive read head of the present invention, which further comprises a non-hygroscopic insulating layer interposed between the substrate and the non-magnetic insulating layer.

(e) Effect, that is, in the present invention, the non-magnetic insulating layer interposed between the conductive magnetic substrate and the magnetoresistive element is replaced with a non-hygroscopic non-magnetic insulating layer directly deposited on the magnetic substrate. At least two types of non-M' = f! By configuring the MR element with an insulating layer, it is possible to increase the insulation resistance between the magnetic substrate and the MR element without deteriorating the magnetic properties of the MR element.

Therefore, the signal quality of the output signal from the playback head can be improved.

(fl Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a main part of an embodiment of a magnetoresistive reproducing head according to the present invention.

In the figure, reference numeral 21 denotes a conductive magnetic substrate made of, for example, Mn-Znn adhesive 1, which is used to eliminate the charge generated by sliding with the magnetic tape recording medium 28 and serves as a shielding magnetic material. Two magnetoresistive elements (hereinafter referred to as Mll elements) made of Ni-Fe permalloy output signal waveforms of opposite polarity to each other on the substrate 21.
As shown in the figure, 22 and 23 are provided through a composite nonmagnetic insulating layer 24 consisting of a non-hygroscopic nonmagnetic insulating layer 24a made of, for example, Al2O3, and a nonmagnetic insulating layer 24b with a smooth surface made of 5i02. It is being

On its upper surface, a shielding magnetic layer 26 made of amorphous Co-Zr or the like and a cover plate 27 made of ceramics or the like are further disposed via a non-magnetic insulating layer 25 made of 5i02, as in the conventional case. It is being

Therefore, it is possible to increase the insulation resistance between the conductive magnetic substrate 21 and the MR element. In addition, the smoothness of the surface of the composite nonmagnetic insulating layer 24 described in n;
Non-magnetic exfoliation 24a of non-hygroscopic H consisting of l2O3 etc.
Since it has a structure in which a non-magnetic insulating layer 241 made of 5iO7 is laminated on top, smoothness comparable to that of a single-layer non-magnetic insulating layer made of 5402 can be obtained. The magnetic properties of the MR element provided on one surface will not deteriorate.

(gl Effects of the Invention As is clear from the above explanation, according to the magnetoresistive playback head of the present invention, a conductive magnetic substrate that has +H is attached to the sliding contact surface of the head that slides in contact with the magnetic tape recording medium. and M
Insulation between R elements 1] (It is possible to increase the resistance.

Therefore, leakage of bias current and external induced noise interference can be easily eliminated, good magnetic reproduction characteristics can be stably obtained, and reliability has been improved. 7-.) It is extremely advantageous to apply to 1.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of a magnetoresistive reproducing head according to the present invention, and FIG. 2 is a sectional view of a main part of a conventional magnetoresistive reproducing head. In the drawing, 21 is a conductive magnetic substrate, 22 and 23 are magnetoresistive elements, 24 is a composite nonmagnetic insulating layer, 24a is a non-hygroscopic nonmagnetic insulating layer, 24b and 25 are 5i02 nonmagnetic insulating layers, 26 27 represents a magnetic material layer for shielding, 27 represents a cover plate, and 28 represents a magnetic tape recording medium.

Claims (1)

[Claims] The head has a structure in which a magnetoresistance effect element with a non-magnetic insulating layer interposed therebetween and a shielding magnetic layer are laminated in this order on a conductive magnetic substrate, and a moisture-absorbing layer is further provided between the substrate and the non-magnetic insulating layer. 1. A magnetoresistive read head characterized by having a magnetic insulating layer interposed therebetween.