JPH0666189B2 - Multilayer magnetic film for magnetic head - Google Patents

Description

The present invention relates to an iron thin film for a magnetic head for use in a recording head capable of magnetically recording information on a recording medium.

[Conventional technology]

Various magnetic heads have been proposed and developed for magnetically recording information on a recording medium and reproducing the recorded information.

By the way, in this magnetic head, it is possible to use, for example, a material in which a thin iron film or the like is grown and formed on a non-magnetic substrate by an ion beam sputtering method, a vapor deposition method or the like as a core constituting the head. Are known. In order to obtain the best possible recording / reproducing characteristics using the magnetic head having the core having such a structure, the saturation magnetostriction λs due to the in-plane applied magnetic field of the iron thin film grown / formed on the substrate is zero. Alternatively, it is desirable that the characteristics be close to that.

[Problems to be solved]

By the way, it is known that the magnetostriction of the iron thin film usually largely depends on the direction of the crystal grains in the film and its distribution (hereinafter referred to as the crystal grain structure). That is, when an iron thin film is grown and formed by a sputtering method or a vapor deposition method, it is impossible to control magnetostriction, and therefore, generally, a saturated magnetostriction λs of zero or near zero (hereinafter abbreviated as zero magnetostriction) is formed. However, even if such a crystal grain structure of zero magnetostriction is once formed, it is very difficult to form a zero magnetostriction similar to that again.

Therefore, in the iron thin film grown and formed by the above method, it is actually very difficult to form the iron thin film while controlling the crystal grain structure to be zero magnetostriction, and it is usually The saturation magnetostriction λs often becomes negative inevitably, and the recording / reproducing characteristics are deteriorated accordingly.

In view of the above-mentioned conventional drawbacks, the present invention has an object to provide a multilayer magnetic film for a magnetic head having a crystal grain structure that causes zero magnetostriction when an in-plane magnetic field is applied. is there.

[Means for solving problems]

That is, the present invention is a multilayer magnetic film used for a magnetic head grown / formed on a substrate, wherein the multilayer magnetic film is an iron thin film having a film thickness of 100Å to 3000Å.
Two or more kinds including a non-magnetic intermediate layer film having a thickness of Å to 200 Å, which is alternately laminated and deposited, and in which the iron thin film becomes at least positive and negative saturation magnetostriction by applying a magnetic field. It is composed of a crystalline material.

[Action]

The multilayer magnetic film for a magnetic head according to the present invention has a non-magnetic intermediate layer film having a constant film thickness, a film thickness within a certain range with the intermediate film being interposed, and two or more types of crystallinity. The thin iron film is formed as an iron thin film, and the thin film having different crystallinity such that the iron thin film has at least positive and negative saturation magnetostriction when a magnetic field is applied is grown or formed to have an appropriate film thickness, respectively, and thus the entire thin film is formed. The saturation magnetostriction can be made to be zero or a value close to this by adding the above, in other words, two or more kinds with different crystallinity are selectively grown to an appropriate film thickness to apply a magnetic field. In this case, the saturation magnetostriction can be freely controlled.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a multilayer magnetic film for a magnetic head according to the present invention. The multilayer magnetic film 1 is grown and formed on a substrate 2, and an intermediate film 3 and two kinds of crystals are formed. It is made of an iron thin film 4 made of a conductive material and has a thickness of 1 micron, and is manufactured by an ion beam sputtering method using an ion beam sputtering apparatus. In addition, in this embodiment, the multilayer magnetic film is manufactured by using the ion beam sputtering method, but the invention is not particularly limited to this, and it may be manufactured by, for example, a vacuum deposition method. .

The intermediate layer film 3 is for allowing the crystals of the iron film to grow according to the individual forming conditions without being affected by the crystallinity of the underlying iron film, and is non-magnetic and has a thickness of 10Å to 200 liters of glass, ceramics, metal, etc. are used.
The intermediate layer film 3 of this embodiment is made of silicon dioxide (Si
It is formed by growing O ₂ ) to about 30 Å.

The iron thin film 4 includes an A layer 4a and a B layer 4b having a constant film thickness ratio.
As shown in FIG. 2, it is composed of a body-centered cubic lattice (BCC) in which nine iron atoms 5 are arranged at each apex and the central portion which together form a cube. The A layer 4a and the B layer 4b can be formed by appropriately changing the acceleration voltage applied to the grid of the ion beam sputtering apparatus. As for the types of various crystalline thin films forming these iron thin films, it is sufficient that they are composed of two or more types which become at least positive and negative saturation magnetostriction by the in-plane magnetic field application, and particularly two types. It is not limited to one. Further, it is desirable that the thickness of each of these thin films be grown so as to fall within the range of 100Å to 3000Å. That is, when the film thickness is less than 100Å, the magnetic properties are likely to deteriorate due to thermal stress, etc., and when the film thickness is more than 3000Å, the crystal grains become too large, which also causes the magnetic property deterioration. It depends on the circumstances. The A layer 4a is formed by setting the accelerating voltage (Vacc) applied to the grid of the ion beam sputtering device to 2 KV as shown in FIG. 3, and the lattice plane (110) with respect to the substrate 2 surface. Crystal grains are formed in such a direction that they are parallel to each other (see FIG. 4), and a constant negative saturation magnetostriction (see FIG. 6) is applied by applying a magnetic field in the in-plane direction of the film (that is, α direction in FIG. 1). It has been found by the present inventor that the above-mentioned characteristics are obtained. The layer A 4a of this embodiment is formed in two layers, one on the substrate 2 and one on the intermediate film 3. On the other hand, the B layer 4b similarly has an acceleration voltage (Vacc).
Is set to 300 V and the crystal grains are grown and formed in a direction such that the lattice plane (200) (see FIG. 5) is parallel to the substrate 2 surface. A constant positive saturation magnetostriction (6th
It has likewise been found by the inventor to have the properties such that The B layer 4b of this embodiment is formed in two layers, one layer on each intermediate layer film 3.

By the way, the ratio T _B / T _A of the film thickness T _B of the B layer 4b to the film thickness T _A of the A layer 4a is such that the iron thin film 4 when a magnetic field is applied in the in-plane direction as shown in FIG. Overall saturation magnetostriction λs
With respect to a substantially linear first-order monotonically decreasing function (where 0T _B / T _A
It has been proved by the experiment of the present inventor that 4) is satisfied. Therefore, the saturation magnetostriction λs can be freely controlled by adjusting the film thickness ratios T _B / T _A of both of them.

Therefore, according to the multilayer magnetic film for a magnetic head according to this embodiment, for example, the film thickness ratio T of the A layer 4a and the B layer 4b is T.
Those A layers 4a so that _B / T _A is about 2.8.
By growing and forming the B layer 4b and the B layer 4b, it is possible to form a zero magnetostriction having excellent recording and reproducing characteristics.

〔effect〕

As described above, according to the multilayer magnetic film for a magnetic head according to the present invention, this multilayer magnetic film has an intermediate film thickness within a certain range as well as an iron thin film having a film thickness within a certain range. Various irons having different crystallinity, each of which is composed of two or more kinds of crystallinity including a layered film and an iron thin film which are alternately laminated and which have at least positive or negative saturation magnetostriction when a magnetic field is applied. By appropriately selecting thin films and forming them to have a specific film thickness, it is possible to freely control magnetostriction of the entire multilayer magnetic film.

Therefore, according to the multilayer magnetic film for a magnetic head according to the present invention, a multilayer magnetic film is formed so as to have, for example, zero magnetostriction and is used for a magnetic head, thereby dramatically improving recording and reproduction. It will be possible.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing the structure of a multilayer magnetic film for a magnetic head according to the present invention, FIG. 2 is a schematic view showing the crystal structure of iron constituting an iron thin film according to the present invention, and FIG. Explanatory diagrams showing the accelerating voltage applied to the grid when forming the A layer and the B layer forming the iron thin film of the multilayer magnetic film for a magnetic head according to the present invention, FIG. 4 and FIG. Area lattice of multilayer magnetic film for magnetic head (1
10) and an explanatory view showing an area lattice (200), and FIG. 6 is a graph showing a relationship between saturation magnetostriction and layers A and B constituting the iron thin film of the multilayer magnetic film for magnetic head according to the present invention,
FIG. 7 is a graph showing the relationship between the saturation magnetostriction and the film thickness ratio of the A layer and the B layer constituting the iron thin film of the magnetic head multilayer magnetic film according to the present invention. 4 ... Iron thin film.

Claims (1)

[Claims] 1. A multilayer magnetic film used for a magnetic head grown / formed on a substrate, which comprises an iron thin film having a film thickness of 100Å to 3000Å and a film thickness of 10Å to 200Å. And a non-magnetic intermediate layer film that is alternately laminated and deposited, and the iron thin film has two or more types of crystallinity, including one that becomes at least positive and negative saturated magnetostriction when a magnetic field is applied. The multi-layered magnetic film for a magnetic head characterized by the above.