JPH0294606A - Iron thin film for magnetic head - Google Patents

Abstract

PURPOSE:To obtain the crystal grain arrangement to become zero magnetic strain at the time of impressing a magnetic field inside a film surface by specifying a diffraction peak strength ratio from a grating face 110 to aforesaid grating face (200) when X-rays are irradiated on the iron thin film having CuKalpha as an X-ray source. CONSTITUTION:A diffraction peak strength ratio from a grating face (100) to the sum of the diffraction peak strength from the grating faces (200) and (110) when X-rays are irradiated on the iron thin film having CuKalpha as an X-ray source shall be in the range 0.035 to 0.5. Thereby, crystal grain arrangement of zero strain can be confirmed merely by performing X-ray diffraction and confirming that the diffraction peak strength ratio in the prescribed range so that the iron thin film can be made to grow and to form while performing sure magnetic strain control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an iron thin film for a magnetic head used in a recording head capable of magnetically recording information on a recording medium.

[Conventional technology]

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

By the way, in this magnetic head, it is possible to use a material such as a thin iron film grown and formed on a non-magnetic substrate by ion beam sputtering or vapor deposition, for example, as the core constituting the head. Are known. In order to obtain as good recording and reproducing characteristics as possible using a magnetic head having a core with such a configuration,
It is desirable that the saturation magnetostriction λS of the iron thin film grown and formed on the substrate due to the in-plane applied magnetic field be zero or close to it. It is known that the magnetostriction of an iron thin film usually depends largely on the direction and distribution of the lattice planes of its crystal grains (hereinafter referred to as crystal grain arrangement). When growing and forming iron thin films by sputtering or vapor deposition, magnetostriction cannot be controlled, so it is generally not possible to form iron thin films with a saturation magnetostriction λS of zero or near zero (hereinafter abbreviated as zero magnetostriction). It is difficult, and even if such a crystal grain arrangement with zero magnetostriction is once produced, it is extremely difficult to form a similar one with zero magnetostriction again.

For this reason, it is actually very difficult to form an iron thin film grown by the above method while controlling the crystal grain arrangement so that it has zero magnetostriction, and it is usually In many cases, the saturation magnetostriction λS inevitably becomes negative.

Therefore, in view of the above-mentioned conventional drawbacks, the present invention provides an iron thin film for a magnetic head having a crystal grain arrangement that exhibits zero magnetostriction when an in-plane magnetic field is applied. An iron thin film used in magnetic heads grown and formed on a substrate in a low-pressure atmosphere, with a purity of 95 a
t or more, and the crystal of this iron thin film has a body-centered cubic lattice (BC
C), and the crystal grains of the iron thin film have lattice planes (110) and lattice planes (200) with respect to the substrate surface.
C
When the iron thin film is irradiated with X-rays using uKα as an X-ray source, the diffraction peak intensity ratio from the lattice plane (110) to the sum of the diffraction peak intensities from the lattice planes (200) and (110) is 0.035. It is in the range of 0.5 to 0.5.

[For production]

The thin film for a magnetic head of the present invention can be confirmed to have a zero magnetostriction crystal grain arrangement simply by performing X-ray diffraction and confirming that a diffraction peak intensity ratio within a predetermined range is obtained. This makes it possible to grow and form iron thin films while performing reliable magnetostriction control.

[Embodiment fD] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an iron thin film 1 for a magnetic head according to the present invention. This iron thin film 1 is grown and formed on a substrate 2, and its crystal structure is cubic as shown in FIG. Nine pieces of iron (Fe) are placed at each vertex position and the center part of the
It has a configuration in which 3 atoms are arranged. Crystal grains formed by a large number of these crystals are formed on the substrate 2.
In this embodiment, the iron thin film 1 is formed in a direction in which the lattice plane (110) (see Fig. 3) and the lattice plane (200) (see Fig. 4) are parallel to the plane by ion beam sputtering. A crystal whose saturation magnetostriction λS due to the application of an in-plane magnetic field is zero magnetostriction (here, electromagnetic strain means 1λS l<lX10-6 as explained earlier). The formation of this electrostrictive crystal structure can be confirmed by X-ray diffraction, which will be explained in detail later. Note that the method for forming the iron thin film 1 may be any method as long as a similar crystal structure can be obtained, and for example, a vacuum evaporation method or the like may of course be used.

Next, a method of manufacturing the iron thin film 1 according to this embodiment using an ion beam sputtering method will be described.

FIG. 5 shows an ion beam sputtering apparatus used in the ion beam sputtering method. In this ion beam sputtering method, argon (Ar") is used as the ions supplied from the ion source 4, and the target Iron material is used for 5.In addition,
In the figure, reference numeral 6 is a grid to which an accelerating voltage for accelerating argon ions (Ar'') is applied, and 7 is a chamber whose pressure is reduced to near a vacuum state.The ion beam sputtering apparatus of this embodiment is, for example, Argon ions (Ar") supplied from an ion source are accelerated to a target 5 by a grid 6 to which an accelerating voltage is applied, for example, IKV, in a chamber 7 in a low-pressure state with an argon gas pressure of 2 to 5 X 10' Torr. It is designed to launch towards the target. When this argon ion (Arc) collides with the target 5 at high speed, iron atoms (Fe) are scattered into the gas from the iron material that is the target 5 and are attached and deposited on the nearby substrate. ing. In this way, when this ion beam sputtering apparatus is used, iron atoms are deposited on the substrate 2 while maintaining a certain crystal structure, that is, mainly (110) and lattice planes parallel to the substrate 2 described above. (200)
The iron thin film 1 is grown and formed in such a state that .

By the way, the conditions for forming the iron thin film 1 to have the specific crystal grain arrangement as mentioned above are as follows: In this example, the film forming speed is 15 to 30 m, and the argon gas pressure is 2 m. Although the accelerating voltage (Vacc) is set as IKV as shown in Fig. 6 when the setting is ~5 x 10-' Torr, the conditions are not particularly limited to this, and the deposition rate and argon gas pressure can be changed. When V is appropriately set under certain conditions, the optimum accelerating voltage (Vacc) at that time can be selected, and the optimum value of this accelerating voltage (V-cc) can be determined by X-ray diffraction as described below.

Regarding the acceleration voltage (Vacc), for example, in the case of the conditions as in the previous example, the acceleration is adjusted so that the magnetostriction is within the range of 1λ'I<1x10-a as shown in FIG. Voltage (Vacc) is 0.36KV-0,
It is sufficient if it is kept within about 53KV.

Next, after growth and formation under various conditions including the above conditions, internal stress is reduced by appropriate heat treatment.
Based on the experimental data shown in Figure 8, which is the experimental data for investigating the saturation magnetostriction λS when an in-plane magnetic field is applied to the iron thin film 1 whose IQ is less than 9 dyn, it is assumed that the iron thin film 1 has a crystal grain arrangement with zero magnetostriction. It will be explained that it is possible to confirm whether or not it has the same by checking the X-ray diffraction peak intensity ratio. As the x7 diffraction device used for this experiment, a conventionally known one as shown in FIG. 9, for example, is used, and this X1 ray diffraction device uses CuKa rays as the ing. Further, reference numeral 9 in the figure is a counter for counting the diffracted CuKa rays.

First, the inventor performed a diffraction experiment on the iron thin film 1 grown and formed under the above conditions using an X-ray diffraction apparatus, and found that the intensity was due to the fact that the lattice plane (110) was parallel to the two surfaces of the substrate. When the crystal grain alignment is present (hereinafter referred to as the first crystal grain alignment), an angle (
When the Bragg dark angle (hereinafter referred to as "angle 2θ") is approximately 44.7 degrees, the X-rays observed due to Bragg reflection from that lattice plane reach a peak, and the lattice plane (200) is relative to the two substrate surfaces. It was found that when the grains have a parallel grain arrangement (hereinafter referred to as the second grain arrangement), the Bragg double angle 2θ peaks at approximately 65 degrees.Therefore, these two types of Bragg double angle 2θ If the intensity of the diffraction line peaks when The saturation magnetostriction λS has a specific negative value (i.e., it shrinks when an in-plane magnetic field is applied).
-For those with a two-grain arrangement, the saturation magnetostriction λS
has a specific positive value (that is, it expands when an in-plane magnetic field is applied), and it cannot be confirmed from this alone whether or not magnetostriction is exactly zero when both of these are added.

Therefore, this inventor proposed that the lattice planes (200) and (110)
Diffraction peak intensity due to diffraction at! (200) and ■(1
10) and the diffraction peak intensity 1 (110) due to diffraction at the lattice plane (110), that is, r (tio) / (
1 (200) +! (110)), it was found that there is a linear-order relationship with respect to saturation magnetostriction λS, as shown in FIG. by this,
The diffraction peak intensity ratio of both of these! (110)/(I (
By examining 200) + 1 (110)), it is possible to confirm whether or not the iron thin film 1 formed using the first and second crystal grain arrangements as main components has zero magnetostriction. becomes. That is, as shown in FIG. 8, for example, the iron thin film 1 crystallized and grown under the conditions described above has a diffraction peak intensity ratio of 0.035 to 0.03 by X-ray diffraction when CuKa rays are used as the X-ray source. If it is confirmed that the iron thin film 1 is within the range of 5, it can be seen that the iron thin film 1 has zero magnetostriction when an in-plane magnetic field is applied.

Therefore, the iron thin film for a magnetic head according to this embodiment was prepared by forming an iron thin film under specific conditions in advance and then applying an appropriate heat treatment to reduce the internal stress of the film to less than I×109 dyn/−. By simply performing f11 diffraction and confirming that the iron thin film has a diffraction peak intensity ratio within a predetermined range, it can be easily determined that the iron thin film has zero magnetostriction when an in-plane magnetic field is applied.

[Effects] As explained above, the iron thin film for a magnetic head according to the present invention is composed of a body-centered cubic lattice (BCC), and the lattice plane (110) and the lattice plane (2
00) are parallel to each other, and the internal stress of the film is less than r x 1o9 dyn/i. Diffraction peak intensity ratio is 0.035 to 0.5
If a thin iron film with a structure falling within the range of 2 is formed and used as a material for a magnetic head, it will have zero magnetostriction when a magnetic field is applied, and the recording and reproducing characteristics will be dramatically improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the state when an iron thin film for a magnetic head according to the present invention is grown and formed on a substrate, and FIG.
The figure is a schematic diagram showing the crystal structure of iron constituting the iron thin film according to the present invention, and FIGS. 3 and 4 show the plane lattice (110) and plane lattice (200) of the iron thin film for a magnetic head according to the invention, respectively. 5 is a schematic configuration diagram showing an ion beam sputtering apparatus for manufacturing an iron thin film for a magnetic head according to the present invention, and FIG. 6 is an explanatory diagram showing an acceleration voltage when manufacturing an iron thin film according to the present invention. In addition, a graph showing the correlation between the Bragg multiplier angle and the diffraction intensity when the iron thin film according to the present invention is diffracted as a sample, and FIG. A graph showing the correlation, FIG. 8 is a graph showing the relationship between the diffraction peak intensity ratio and saturation magnetostriction when an iron thin film for a magnetic head according to the present invention is subjected to X-ray diffraction, and FIG. 9 is a graph showing a magnetic head according to the present invention. FIG. 10 is an explanatory diagram showing the Bragg angle when X-rays are irradiated to the iron thin film for a magnetic head according to the present invention. . 2... Substrate, 1... Iron thin film. Figure 1

Claims (1)

[Claims] (1) An iron thin film used in a magnetic head that is grown and formed on a substrate in a low-pressure atmosphere close to vacuum.The iron purity is 95 at% or more, and the crystal structure of this iron thin film is a body-centered cubic lattice ( BCC), and the crystal grains of the iron thin film have a lattice plane (110
) and lattice planes (200) are parallel to each other, and the internal stress of the film is 1×10^9 dyn/cm^2 or less. When the iron thin film is irradiated with X-rays using CuKα as an X-ray source, the diffraction peak intensity ratio from the lattice plane (110) to the lattice plane (200) is 0.0.
An iron thin film for a magnetic head, characterized in that the iron thickness is in the range of 35 to 0.5.