JPH01189013A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To release a partial abrasion and to prevent the generation of a spacing loss by successively changing the hardness of a protecting layer provided on an upper magnetic layer so as to be equal to or below that of a magnetic layer at the upper magnetic layer side and to be gradually increased as it is separated from the upper magnetic layer. CONSTITUTION:On a substrate 10, a lower magnetic layer 11, a non-magnetic insulating layer 12, a coil conductor layer 13, an upper magnetic layer 16, etc., are formed, and thereafter, a protecting layer 17 is formed on them. Here, since the hardness of the protecting layer 17 is made into a value equal to or below that of the magnetic layer 16, for the abrasion generated due to the sliding of a recording medium, the abrasion quantities of the protecting layer 17 and magnetic layer 16 are made approximately equal, and consequently, the partial abrasion can be released. The layer is made into a successive changing layer in which the hardness is made equal to or below that of the magnetic layer 16 in the part of the protecting layer 17 near to the magnetic layer 16 and the hardness is gradually hardened as it is separated from the magnetic layer 16, and when the hardness of the part corresponding to a most outer layer side is sufficiently hardened, even a protecting plate 19 can be omitted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an N-film magnetic head, and more specifically to a thin-film magnetic head in which a protective layer laminated on a magnetic layer is improved.

[Prior Art] Conventionally, a thin film magnetic head is constructed as shown in FIG.

FIG. 4 shows a cross-sectional view of a conventional thin-film magnetic head, in which a plurality of magnetic layers 2 made of sendust, amorphous, etc., and conductive layers are formed on a substrate 1 made of a wear-resistant material such as ferrite or sapphire. The coil conductor layer 3 made of metal, the insulating layer 4 and gap layer 5 that serve as insulators between the coil conductor layer 3 and the magnetic layer 2, and the protective layer 7 that protects the magnetic layer 2 from wear due to running of the recording medium 6 are sputtered.
It is attached by a method such as vapor deposition and processed into a predetermined shape by photo-etching.

In addition, the above-mentioned guarantee! ! i layer 7 contains siO2,l 203
etc. are used.

Furthermore, the thin film magnetic head is disclosed in, for example, Japanese Patent Application Laid-Open No. 59-77.
No. 617, No. 60-138714, No. 61-2400
As described in Publication No. 7, etc., a protective plate 9 was adhered with an adhesive layer 8 of glass, resin, etc. on the protective layer 7, which was flattened in consideration of wear due to running of the recording medium. Consists of composition.

[Problems to be Solved by the Invention] However, in the above structure, since the material of the f1 layer or the substrate is harder than the magnetic layer (for example, Gockers hardness Hv<K9/1rys2),
The magnetic layer is the substrate in the shape shown by the broken line.

This caused so-called uneven wear, in which the protective layer was worn more than the protective layer, and the distance between the gap portion and the magnetic recording medium increased, resulting in a so-called spacing loss, in which the reproduction output decreased.

Specifically, the Vickers hardness Hv of sendust and amorphous that form the magnetic layer is 600 to 650/(g/ll11
2, whereas the Vickers hardness Hv of SiO2 forming the protective layer is 750 to 800 Kl/rm 2°AJ1203 and 800 to 900 Kg/foot2. In addition, the ferrite that forms the substrate is 650Kg/In! R
2. Sapphire is 12001 (g/t, #+2).

The purpose of the present invention was achieved based on the above circumstances, and
It is an object of the present invention to provide a thin film magnetic head that eliminates the above uneven wear and prevents spacing loss.

[Means and effects for solving the problem] That is, the above object of the present invention is to provide a lower magnetic layer, a coil conductor layer, a
In an a-film magnetic head in which an insulating layer and an upper magnetic layer are formed, and a protective layer is provided on the upper magnetic layer, the retaining layer has a hardness equal to or lower than that of the magnetic layer on the upper magnetic layer side. This is achieved by a thin-film magnetic head characterized by comprising a continuously variable layer having hardness that gradually increases with increasing distance from the upper magnetic layer.

By setting the hardness of the protective layer to be equal to or smaller than that of the magnetic layer, the wear element of the protective layer becomes almost equal to that of the magnetic layer during wear caused by sliding of the recording medium, thus eliminating uneven wear. be done. On the other hand, especially when the protective layer is made of a material having lower hardness than the magnetic layer, the protective layer wears out quickly and the life of the head is shortened. Therefore, the protective layer is configured as a continuously variable layer whose hardness is equal to or lower than that of the magnetic layer in the vicinity of the magnetic layer, and gradually becomes harder as the distance from the magnetic layer increases. In particular, if the part corresponding to the black outer layer side is sufficiently hard and has a hardness equivalent to that of a protective plate (for example, a Vickers hardness Hv of 1000 to 12001 (about R/NR2)), the protective plate The board can also be omitted.

The present inventor conducted various experiments and found that when the magnetic layer has a Vickers hardness of 600 to 650 Kg/l1u12, the protective layer has a Vickers hardness of 300 to 6 in the vicinity of the magnetic layer.
50Kg/l1m2, 650 in the area farthest from the magnetic layer
Suitable results were obtained by setting the Vickers hardness to a value of Kg/tea 2 or more, and by configuring the hardness to gradually and continuously change between the two regions.

Implementation example] Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a sectional view of the thin film magnetic head of the present invention.

In the figure, a ferromagnetic material of Co--Nb--Zr alloy was deposited to a thickness of 15 μm on a Zn-ferrite substrate 10 by sputtering to form a lower magnetic layer 11. Next, the first non-magnetic insulating layer 12 is deposited several μm thick on the lower magnetic layer 11 by sputtering, and a conductor such as Cu or A1, which will become the winding, is deposited on top of it by sputtering to form a coil conductor in a predetermined shape. 13 is formed by etching, a second non-magnetic insulating layer 14 is formed thereon to insulate the coil conductor layer 13 and the upper magnetic layer 16, and a front gap portion and a rear gap portion are formed. A nonmagnetic insulating layer 15 was attached to the gap to serve as a head gap. And the lower magnetic layer 11
A 15 μm thick metal magnetic material of Go-Nb-Zr alloy, which is magnetically coupled to the upper magnetic layer 16, is deposited by sputtering.
was formed.

Next, the main part of the present invention is the protection ii! ! Layer 17 to top 11
was formed on the sexual layer 16. The protective layer 17 is provided as a continuously variable layer whose hardness gradually increases as the film is formed. That is, the protective layer 11 was formed using a reactive vapor deposition method (evaporation R source=SRO, film formation rate=1500 persons/M, degree of vacuum=
The oxygen gas concentration decreases at the initial stage of deposition and increases as the deposition progresses (Oxygen gas partial pressure - initial stage: 24x10'Torr, intermediate: 8x10'Torr, final stage: 4 x 1O-
4Torr) L/te, the hardness is changed. As a result, the Vickers hardness of the preservation II layer is 4SO in the initial part.
Ky/shoes 2, 600 Kg/rm in the middle part
2. A hardness of 800 Kg/m2 and continuously changing in the final part was obtained.

FIG. 2 shows a reactive vapor deposition apparatus for forming the protective layer 16. That is, this apparatus has a configuration in which an electron beam evaporation apparatus and an RF sputtering apparatus are combined.

A crucible 20 in the reaction vessel contains Si as a vapor deposition material 21.
Oxygen is contained, and an electron beam is applied to it by an electron gun 22 to locally heat it and evaporate it.

On the other hand, a pair of parallel plate electrodes are placed inside the container, and the lower electrode 23 is grounded and provided at an earth potential, and has a plurality of gas ejection holes (not shown) to supply oxygen from the outside. supply On the other hand, the upper layer electrode 24 holds the substrate 25 formed up to the magnetic layer, and is applied with a high frequency voltage by a high frequency bias source 26 via a capacitor C. As a result, plasma is generated between the electrodes, and at the same time, the voltage application side electrode (upper layer electrode) is set to a negative potential and oxygen ions are irradiated onto the substrate.

A recording medium is placed on the surface of the thin film magnetic head configured as described above.
After running for 1,000 hours, uneven wear was observed. Uneven wear was determined by observing interference fringes with an optical flat and examining the level difference between the magnetic layer and the protective layer, and no level difference was observed.

FIG. 3 shows a device for ring-ringing another embodiment of the invention.

This device performs a co-evaporation method, and two crucibles 31 and 32 placed in a container contain different evaporation materials GeO and SiO□, respectively, and an electron beam 33 irradiates each evaporation material. is configured to be The amount of beam applied to each evaporation material is independently adjustable, and a large GeO2 molar ratio is deposited at the initial stage of vapor deposition, and the GeO2 molar ratio is lowered as the vapor deposition progresses. As a result, in contrast to the thin film magnetic head whose structure up to the upper magnetic layer is the same as that of the first embodiment, a magnetic layer made of GeO2.S i O2 is formed on the upper magnetic layer. The layers were formed as continuously variable layers whose composition ratios were varied.

Note that the film forming conditions in the above apparatus are a degree of vacuum of 2 x 10
Below Torr, sweep time ratio (Gf!02/5i
02)=Initial: 1.5/101 Intermediate: 1/10
, final stage: O/10, emission electricity 1=Ge O2
: i.

mA, S i O2: 30 mA, so that the Vickers hardness in the initial part was 400 K9/
m2, 550 K9/la2 in the middle part, 800 Kg/In1R2 in the final part, and a hardness that continuously changes was obtained. When the thin film magnetic head constructed in this manner was observed using the same method as in Example 1, no uneven wear was observed. Further, the absolute amount of wear was observed using a depth marker and was found to be approximately 0.6μ/1000H, indicating that a practically sufficient head life was ensured.

[Effects of the Invention] As described above, according to the thin film magnetic head of the present invention, the protective layer laminated on the magnetic layer has a hardness higher than that of the magnetic layer from an initial portion having a hardness lower than that of the magnetic layer. By forming the continuously variable layer up to the final portion, occurrence of uneven wear due to running of the recording medium can be suitably prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a thin film magnetic head constructed based on the present invention, FIG. 2 is a diagram illustrating an apparatus used in the embodiment of FIG. 1, and FIG. 3 is an apparatus used in other embodiments. FIG. 4 is a sectional view of a thin film magnetic head having a conventional structure. 10: Zn-ferrite substrate, 11: Lower magnetic layer, 12: First non-magnetic insulating layer 13: Coil conductor layer, 14
: Second nonmagnetic insulation Ff115: Nonmagnetic insulation layer 16: Upper magnetic layer, 17: Protective layer, 18: Adhesive layer,
19: Protective plate, 20, 31.32: Crucible,
21: Vapor deposition material, 22: Electron gun, 23 Ni-do layer electrode, 24 Ni-H layer electrode, 25: Substrate, 33: Electron beam. 1121 Figure 2 L: Figure 1 3 Figure 4

Claims (1)

[Claims] In a thin film magnetic head in which a lower magnetic layer, a coil conductor layer, an insulating layer, and an upper magnetic layer are formed on a substrate, and a protective layer is provided on the upper magnetic layer, the protective layer is equal to the magnetic layer on the upper magnetic layer side. 1. A thin film magnetic head comprising a continuously variable layer having a hardness of 1 or lower, and a continuously variable layer having a hardness that gradually increases as the distance from the upper magnetic layer increases.