JPS61104412A - Magnetic head - Google Patents

Abstract

PURPOSE:To make equal the coeffs. of thermal expansion of a nonmagnetic base and thin magnetic film and to obviate the exfoliation of the thin magnetic film and the deterioration of the magnetic characteristic in a magnetic head combined and united with the nonmagnetic base and thin magnetic film by consisting the nonmagnetic base of a specific ceramic compsn. CONSTITUTION:The Na2O-Ta2O5 ceramic compsn. is used as the nonmagnetic substrate. The Na2O-Ta2O5 ceramic compsn. has the compsn. expressed by the generation formula xNa2O.yTa2O5 and the compsn. range thereof is set at 0.85<=x/y<=1.00. The coefft. of linear expansion alpha is <130X10<-7>/ deg.C which is too small as compared to the thin magnetic film is x/y is <0.85. Sintering is defective and the ceramic compsn. having good quality is not obtainable when x/y exceeds 1.00. The coefft. of linear expansion alpha of the ceramic compsn. is controlled to 130-170X10<-7>/ deg.C when x/y is set at 0.85<=x/y<=1.00. A small amt. of additive may be added to the ceramic compsn. in order to improve the sinterability thereof. Such additive is exemplified by Li2O, etc. for substituting Na with a small amt. of the other alkali metal and Nb2O5, etc. for substituting Ta.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic head in which a non-magnetic support and a magnetic thin film are compositely integrated, such as a thin-film magnetic head or a composite magnetic head. More specifically, the present invention relates to improvements in non-magnetic supports.

[Conventional technology]

Conventionally, in the field of magnetic recording, advances have been made to increase the density and frequency of recording signals, and in response to this higher density recording, magnetic powder such as Fe, Co, N
Magnetic recording media with high coercive force Hc are now being used, such as so-called metal tapes using ferromagnetic metal powder such as i, and so-called vapor-deposited tapes in which ferromagnetic metal materials are deposited on a base film by vapor deposition. It has become. Therefore, head materials for magnetic heads used for recording and reproduction are required to have a high saturation magnetic flux density Bs.

Alternatively, with the above-mentioned high-density recording, the track width of the magnetic pattern recorded on the magnetic recording medium is also becoming narrower, and the track width of the magnetic head is also required to be extremely narrow.

In response to the above-mentioned requirements, conventionally, so-called composite magnetic heads have been developed, for example, in which a non-magnetic support and a metal magnetic thin film serving as a magnetic core are laminated and this magnetic thin film portion is used as a track portion.
Thin-film magnetic heads and the like have been proposed in which a multi-layered metal magnetic thin film or conductive metal thin film is laminated on a non-magnetic substrate with an insulating thin film interposed therebetween, and in this way, the application of magnetic thin films has progressed in the field of magnetic recording. ing.

By the way, when the above-mentioned magnetic thin film is used in a magnetic head etc., a ceramic substrate is usually used as its support, but it is known that the coefficient of thermal expansion of conventional ceramic substrates is considerably lower than that of metal materials. 6 For example, the coefficient of linear expansion α of permalloy, sendust, etc. used in thin-film magnetic heads is 130 to 160
3 series ceramic 90~l OOX 10/'C, Ca
It is a TiO3 ceramic and is quite small, about 100 to 120X10/'C.

For this reason, these few conventional magnetic heads have a drawback in that the magnetic thin film is likely to peel off from the ceramic substrate when heat treatment is performed for manufacturing reasons.

Furthermore, when considering the application of metal materials (magnetic materials) that have magnetostriction that is not completely zero, especially to thin-film magnetic heads, distortion occurs during thin film formation or during cooling after heat treatment due to the difference in linear expansion coefficient. is introduced, and this strain may introduce magnetic anisotropy into the metal material through magnetostriction, causing deterioration of magnetic permeability in the metal thin film.

[Problem that the invention seeks to solve]

Therefore, the present invention has been proposed in order to eliminate the drawbacks of the above-mentioned conventional products, and the present invention is such that the coefficient of thermal expansion of the non-magnetic support and the magnetic thin film is the same, and the present invention prevents peeling of the magnetic thin film and deterioration of magnetic properties. It is an object of the present invention to provide a highly reliable magnetic head that does not cause.

[Means for solving problems]

In order to achieve the above object, the present invention provides a magnetic head in which a non-magnetic support and a magnetic thin film are compositely integrated, wherein the non-magnetic support has a general formula of XNa, O.
5, and the composition range is 0.85≦x/y≦1.00.

[Effect]

In this way, the general formula xNa is used as a nonmagnetic support.

It is expressed as 0-y Ta105 and its composition range is 0.8
By using a ceramic composition in which 5≦x/y≦1.00, the nonmagnetic support and the magnetic metal have the same linear expansion coefficient α, which prevents peeling of the magnetic metal and decrease of magnetic permeability due to heat treatment. Deterioration is prevented.

〔Example〕

An embodiment of a magnetic head to which the present invention is applied will be described below with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to a thin film magnetic head.

In this example, a non-magnetic substrate 1 is made of a Na, O-T a205 ceramic composition, and a lower magnetic film 2, which is one of the magnetic films constituting a magnetic path on the non-magnetic substrate 1, is made of, for example, a Sendust thin film. It is formed by etc.

Here, the Na2Q-Tal○5-based magnetic ceramic composition has a composition represented by the general formula xNalo-yTaYO8, and the composition range is 0.85≦x/y≦1. 0
Set to 0.

In the ceramic composition used for the non-magnetic support 1, the composition range is important, and the X/y is 0.85.
If the coefficient of linear expansion is less than α<130×10/°C, it will be too small compared to a magnetic thin film, and on the other hand, x/y will be 1.00.
If it exceeds this amount, sintering defects will occur and a good quality porcelain composition will not be obtained. On the other hand, the value of x/y above is 0.85≦x/y
≦l.

By setting OO, the linear expansion coefficient α of the ceramic composition is controlled to 130 to 170×lO/”c.

Furthermore, a small amount of additives may be added to the above ceramic composition to improve sinterability. Such additives include
For example, L for substituting a small amount of Na with other alkali metals.
too, KzO, etc., N b, 05 replacing Ta
, or other materials such as CaO and Sr○.

Further, the form of the ceramic composition used for the non-magnetic support 1 may be either a sintered body or a single crystal.

By the way, as a method for producing the above-mentioned porcelain composition, specifically, the following method can be used.

For example, first, raw material powders of Na, CO, and TaO5 having a purity of 99.9% or more are prepared.

Next, each of these raw material powders is weighed so as to have a predetermined composition, mixed with a chopstick using ethanol as a mixed solvent, and then heated to remove the ethanol.

Subsequently, the molded product is press-molded at a pressure of 1000 kg/cd, and the molded product is calcined in air at 900° C. for 3 hours.

Further, this calcined product is ground in a mortar, mixed again in a ball mill using ethanol as a mixing medium, and then the ethanol is removed by heating. Thereafter, it is press-molded at a pressure of 1500°C/ad and fired in air at 1350°C to 1500°C for 3 hours to obtain a porcelain composition.

The porcelain composition obtained in this way is processed into a prismatic shape,
When the coefficient of linear expansion α of the porcelain composition was measured with a linear expansion needle in the temperature range of 40 to 600°C, it was found that the coefficient of linear expansion α of the porcelain composition increased as the proportion of Nazo increased, and in particular, the value of x/y was 0.85. It has been found that when the coefficient of linear expansion α is exceeded, the coefficient of linear expansion α becomes 130 to 170×lO/′c, which is comparable to the coefficient of linear expansion of metal.

On the other hand, a signal conductor 4 is formed on the lower magnetic film 2 via an insulating Ft3 made of SiO, etc. The signal conductor 4 is formed by etching a copper thin film deposited by a method such as sputtering, and records and reproduces signals in a closed magnetic path formed by the lower magnetic film 2 and the upper magnetic film described below. It is arranged to supply.

Furthermore, an upper magnetic film 6 made of sendust or the like is formed on the signal conductor 4 with a second insulating layer 5 interposed therebetween.
The rear end 6a of the upper magnetic film 6 is connected to the lower magnetic M*2 to form a bank gap, and the front end faces the lower magnetic film 2 via the insulating layer 3 to form an operating gap. It looks like this.

The thin-film magnetic head configured in this manner further includes S.
A protective film 7 such as 102- is provided, and a non-magnetic protective plate 9 is pasted with fused glass 8.

Note that this nonmagnetic protection plate 9 is made of the same ceramic composition as the nonmagnetic substrate 1 described above.

As is clear from the above description, in the thin film magnetic head that is compatible with the present invention, since the coefficient of thermal expansion of the nonmagnetic substrate 1 and the coefficient of thermal expansion of the lower magnetic film 2 are almost equal, for example, the magnetic properties of the magnetic thin film are The lower magnetic film 2 will not peel off even if heat treatment is applied to improve the magnetic properties or heat treatment during manufacturing processes such as glass fusion and glass bonding. In addition, magnetic anisotropy due to a difference in linear expansion coefficients does not occur in the lower magnetic film 2, and hence no decrease in magnetic permeability occurs.

Next, other embodiments of the present invention will be described.

FIG. 2 shows an example in which the present invention is applied to a composite magnetic head.

In this magnetic head, metal magnetic layers 11, 12 are sandwiched between non-magnetic guard materials 13, 14 or 15° 16, respectively, and the abutting surfaces of these metal magnetic layers 11, 12 track the thickness of these metal magnetic layers M 11, 12. The working gap 17 is configured to have a width.

Further, the magnetic head is provided with a winding groove 18, and by winding a conductor coil (not shown) in this winding groove 18, a recording/reproducing signal is supplied to the metal magnetic layer 11, 12. There is.

Here, the metal magnetic Fjll, 12 is a method of laminating thin strips of metal magnetic material, such as sendust alloy or amorphous alloy, which is usually used in this type of magnetic head,
It is formed by vacuum thin film forming means such as sputtering or vapor deposition of a ferromagnetic metal material.

On the other hand, the non-magnetic guard material 13.14 and the non-magnetic guard material 15.16 have a linear expansion coefficient α comparable to that of the metal magnetic Fill, 12, similar to the non-magnetic support 1 of the previous embodiment.
It is made of a porcelain composition with

Therefore, as in the previous embodiment, peeling may occur in the metal magnetic layer 11, 12 due to the difference in thermal expansion coefficient between these non-magnetic guard materials 13, 14, 15, 16 and the metal magnetic layer 11, 12. There isn't.

〔Effect of the invention〕

As is clear from the above description, in the present invention,
As a non-magnetic support for a magnetic head in which a non-magnetic support and a magnetic thin film are compositely integrated, such as a thin-film magnetic head or a composite magnetic head, the general formula XNaz0.7 T a, O,
The composition range is 0.85≦x/y≦1. Since the ceramic composition OO is used, the linear expansion coefficients of the nonmagnetic support and the magnetic thin film are approximately equal.

Therefore, it is possible to provide a highly reliable magnetic head that does not cause separation between the nonmagnetic support and the magnetic thin film or deterioration of magnetic properties such as magnetic permeability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example in which the present invention is applied to a thin film magnetic head, and FIG. 2 is an external perspective view showing an example in which the present invention is applied to a composite type magnetic head. 1... Nonmagnetic substrate (nonmagnetic support) 2... Lower magnetic film (magnetic thin film) 6... Upper magnetic film (magnetic thin film) 11.12... Metal magnetic layer (magnetic layer II) 13 .14
,15.16

Claims (1)

[Claims] In a magnetic head in which a non-magnetic support and a magnetic thin film are integrated into a composite, the non-magnetic support has the general formula xNa_2O.
A magnetic head comprising a ceramic composition having a composition represented by yTa_2O_5 and having a composition range of 0.85≦x/y≦1.00.