JPH0334406A - Multilayer type ferromagnetic substance - Google Patents

Abstract

PURPOSE:To obtain high saturation magnetic flux density, high magnetic permeability, and magnetostriction constants in the vicinity of zero, and improve the heat resistance stability of soft magnetic characteristics, by alternately laminating iron based ferromagnetic layers and intermediate layers on a substrate, which layers contain nitride and oxide of silicon and either one or more kinds of Nb or niobium nitride. CONSTITUTION:Ferromagnetic material layers composed of iron based material and intermediate layers composed of mixture containing at least one kind selected from nitride and oxide of silicon and either one kind of Nb and niobium nitride are alternately laminated on a substrate. As the nitride of silicon, compound expressed by a general formula SixNy (non-equibrium phase is contained and 0.4<=x/y<=1.1) is desirable. As the oxide, compound expressed by a general formula SiOZ ((z) is a number in the range of 1-2) is desirable. Thereby a multilayer type ferromagnetic substance is obtained, which has high saturation magnetic flux density, high magnetic permeability, and magnetostriction constants in the vicinity of zero, and is excellent in the heat resistance stability of soft magnetic characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel multilayer ferromagnetic material. More specifically, the present invention has excellent features such as high saturation magnetic flux density, high magnetic permeability, and magnetostriction constant near zero, as well as good thermal stability of soft magnetic properties, The present invention relates to a multilayer ferromagnetic material that can be suitably used as a material for heads, thin film inductors, etc.

BACKGROUND OF THE INVENTION In recent years, in magnetic recording and reproducing devices such as VTRs, the recording signal density and frequency have been increased. So-called metal tapes using ferromagnetic metal powders such as ferromagnetic metal powders, and so-called vapor-deposited tapes in which ferromagnetic metal materials are deposited on a base film by means such as vapor deposition, are being put into practical use.

Since such a magnetic recording medium has a high coercive force, the head material of the magnetic head used for recording is required to have a high saturation magnetic flux density. In particular, in thin-film magnetic heads, it is necessary to reduce the thickness of the magnetic pole tip of the head in order to improve the recording density.1 To prevent the magnetic saturation of the magnetic pole tip that occurs due to this, a magnetic material with a high saturation magnetic flux density is used. Is required. In addition, in the perpendicular magnetic recording system, for example, the main pole of a single-pole magnetic head for perpendicular magnetic recording is extremely thin, about 2 μm, so it is easily magnetically saturated during recording and reproduction. A magnetic head material with a saturation magnetic flux density is required.

On the other hand, the magnetic head material must have high magnetic permeability from the viewpoint of head reproduction efficiency, and therefore it is desirable that the magnetostriction constant be close to zero.

As magnetic materials with such high saturation magnetic flux density, high magnetic permeability, and low magnetostriction constant, and soft magnetic properties, various materials have been developed. permalloy), iron-aluminum-silicon alloy (
sendust), cobalt-based amorphous alloys such as iron-silicon-gallium-ruthenium alloys, cobalt-zirconium-niobium alloys, iron-silicon alloys (Japanese Unexamined Patent Publication No. 172705/1983), iron-chromium alloys ( Japanese Patent Application Laid-Open No. 63-60256) is known.

However, among these iron-based magnetic materials, the saturation magnetic flux density (Bms) is within the range of 8 to 12 kG, and the number (λS)
It is necessary that both the magnetic crystalline anisotropy constant (K) and the magnetocrystalline anisotropy constant (K) be near zero, and this requires the addition of a large amount of nonmagnetic elements, so the saturation magnetic flux density is only about 12 kG at most. The reality is that we are not getting it.

On the other hand, various iron nitride-based materials are known as having a large saturation magnetic flux density of about 20 kG or more, but these cannot necessarily be said to be satisfactory in terms of reproducibility or have a low coercive force. There were problems such as difficulty in suppressing it.

In addition, since these iron-based magnetic materials have a large magnetocrystalline anisotropy constant, when used as a single layer film, the volume of crystal grains is large, and the resulting magnetocrystalline anisotropy is greatly affected, making it soft. The disadvantage is that the magnetic properties are significantly degraded.

In order to improve these drawbacks, it is desirable to make the crystal grains finer and suppress the influence of magnetocrystalline anisotropy. Therefore, by forming multiple layers, the thickness of a single ferromagnetic material layer can be reduced. Attempts have been made to improve the soft magnetic properties by thinning the crystal grains and making the crystal grains finer.

As a multilayer magnetic material using α-Fe as a ferromagnetic material layer, for example, one in which iron-based ferromagnetic material layers and intermediate layers made of silicon dioxide are alternately laminated (Japanese Patent Laid-Open No. 63-58806) , ferromagnetic material layers made of iron-chromium alloy and intermediate layers made of silicon dioxide or permalloy are alternately laminated (Japanese Patent Laid-Open No. 63-60256), etc., in which silicon dioxide, a non-magnetic material, is used for the intermediate layer. This is the first known thing.

However, although such a multilayer magnetic material using silicon dioxide as an intermediate layer has a certain degree of excellent effect in improving soft magnetic properties, the heat resistance stability of the soft magnetic properties is not necessarily sufficient. This is 200 to 60
At a temperature of about 0°C, the silicon dioxide undergoes diffusion bonding with iron in the ferromagnetic material layer, or the crystal grains of the ferromagnetic material layer expand, resulting in a decrease in the characteristics. It is. On the other hand, examples of ferromagnetic materials containing iron and gold and containing silicon and ruthenium include iron-silicon alloys (Japanese Patent Publication No. 1-8566) and iron-silicon-ruthenium alloys (European Patent No. 144.150). number specification)
, iron-ruthenium alloy (Japanese Unexamined Patent Publication No. 1398/1983), etc. are known.

Among these, iron-silicon alloys have saturation magnetic flux density (B
ms) and magnetic permeability (μiac), but lacks corrosion resistance. Among these, those with a silicon content of 6.5% by weight have a magnetostriction constant (λS) near zero, and attempts have been made to apply them to magnetic heads, but there are problems with corrosion resistance. , 1 has not yet been put into practical use.

Next, iron-silicon-ruthenium alloys are used as thin film materials for magnetic heads for high-density magnetic recording, but their magnetostriction constants are large in regions with low silicon content, making them unusable as heads; In a region where the amount is large, the magnetostriction constant is close to zero, but the saturation magnetic flux density decreases to 15 kG or less, which inevitably limits the range of use.

On the other hand, iron-ruthenium alloys have a high saturation magnetic flux density,
Although it has the property of having a magnetostriction constant close to zero, it has a low magnetic permeability, which is only about 1800 at most even when multilayered, and furthermore, it decreases to less than 1000 due to thermal processing, which poses a practical problem.

Problems to be Solved by the Invention Under these circumstances, the present invention solves the problem of high saturation magnetic flux density,
This was done for the purpose of providing a multilayer ferromagnetic material that has high magnetic permeability and a magnetostriction constant near zero, and also has good heat resistance stability of soft magnetic properties.

Means for Solving the Problems As a result of extensive research in order to develop a multilayer ferromagnetic material having the above-mentioned excellent characteristics, the present inventors have developed a method using a specific silicon compound as an intermediate layer together with an iron-based ferromagnetic layer. The inventors discovered that a mixture containing a nitride of a specific metal and a nitride of a specific metal, and alternately layered these on a substrate, is suitable for the purpose, and based on this knowledge, the present invention was completed. .

That is, the present invention provides a substrate with (4) a ferromagnetic material layer selected from iron-based materials, and (B) at least one selected from (a) silicon nitrides and oxides, and (b) Nb or The present invention provides a multilayer ferromagnetic material characterized by alternately laminating intermediate layers made of a mixture containing any one type of niobium nitride.

The present invention will be explained in detail below.

In the multilayered ferromagnetic material of the present invention, the iron-based ferromagnetic material used as the magnetic layer may have a high saturation magnetic flux density, high magnetic permeability, and a magnetostriction constant near zero. There are no particular limitations, and iron-based ferromagnetic materials commonly used in magnetic thin films for magnetic heads and the like can be used. Examples of such iron-based ferromagnetic materials include P-ROI, Fe-5i-At-based alloy, Fe-3i-
Ru alloy, Fe-5i alloy, Fe-Ni-M.

Examples include Fe-Ga-5i-based alloys, Fe-Ga-5i-based alloys, and Fe-Cr-based alloys, and each of these may be used alone or in combination of two or more.

The intermediate layer applied to the multilayered ferromagnetic material of the present invention contains (a) at least one selected from silicon nitrides and oxides, and (b) one or more of Nb or niobium nitride. do. Although the heat resistance stability of the soft magnetic properties is not sufficient with only the silicon compound of the component (A) without adding the metal nitride of the component (B), it is possible to add an intermediate layer by adding the component (B). The layer becomes thermally stable and exhibits good soft magnetic properties. The silicon nitride in the IfC component (a) is expressed by the general formula SixNy (including non-equilibrium phases, where X and y are numbers that satisfy the relationship of formula 0.4≦X/y≦1.1). The compounds shown are preferred. - way,
The silicon oxide has the general formula 5iOz (however, 2
is a number in the range of 1 to 2) are preferred.

There are no particular restrictions on the substrate used for the multilayered ferromagnetic material of the present invention, and it may be one that has been conventionally used for magnetic thin films for magnetic heads, such as glass or plastic with a polymer layer that is cured by ultraviolet light. A substrate made of a transparent material such as acrylic resin, styrene resin, polycarbonate resin, vinyl acetate resin, vinyl chloride resin, or polyolefin resin, or a substrate made of an opaque material such as aluminum or ferrite can be used. .

The multilayered ferromagnetic material of the present invention is obtained by laminating the above-mentioned magnetic layers and intermediate layers alternately on these substrates, and is obtained by laminating one single layer with a thinner thickness. It is preferable to reduce the thickness of the layer and increase the number of laminated layers, but from the viewpoint of economy and workability, the thickness of the magnetic layer is usually in the range of 200 to 100A, and the thickness of the intermediate layer is 10 to 10A. It is preferable that the number of laminated layers is in the range of 4 to 140 layers, and the total thickness is in the range of 0.4 to 3 μm.

In the present invention, there are no particular limitations on the method of forming the magnetic layer and intermediate layer, and any method may be used from among the methods normally used for forming thin films, such as vacuum evaporation, sputtering, ion blating, and CVD. can be selected and used. In addition, when forming an intermediate layer containing silicon nitride and any one of (b) Nb or niobium nitride, the vapor deposition raw material contains Si or S.
Evaporation is carried out using a mixed gas containing ix'Ny' or both and the above (b) Nb in a predetermined ratio and containing nitrogen in a predetermined ratio as an atmospheric gas, or preferably a mixed gas of argon and nitrogen. That's fine. At this time, the Si
The V value of Ny can be controlled. In addition, when forming an intermediate layer consisting of a mixture of silicon oxide and metal nitride (component (b)), the vapor deposition raw material may be SiO or 5iO2.
Alternatively, Nb may be contained in a predetermined ratio in combination with both of them and (b) above, and vapor deposition may be performed using an atmospheric gas containing nitrogen and oxygen in the same manner as described above. At this time, by appropriately selecting the usage ratio of SiO and 5i02, the binary value of Sioz in the formed intermediate layer can be controlled.

Effects of the Invention The multilayer ferromagnetic material of the present invention has a ferromagnetic layer made of an iron-based material, and an intermediate layer containing at least one of Nb or niobium nitride in silicon nitride or oxide, on a substrate. It has excellent characteristics such as high saturation magnetic flux density, high magnetic permeability, and magnetostriction constant near zero, as well as good thermal stability of soft magnetic properties. It is suitably used as a magnetic film, etc.

Examples Next, the present invention will be explained in more detail with reference to examples.
The present invention is not limited in any way by these examples.

The composition, coercive force, and magnetic permeability of the obtained multilayered ferromagnetic material were determined as follows.

(1) Composition EPMA (Electron Probe Micro
oanalysis).

(2) Coercive force He (Oe) Measurements were made using a thin film histroscope.

(3) Magnetic permeability μiac Determined by applying a ferrite yoke to the film surface so that the measurement magnetic field is applied in the direction of the hard magnetization axis, and measuring the inductance using an impedance analyzer with a magnetic field of 3 moe and a measurement frequency of 5 MHz. Ta.

Example 1゜RF
Sputtering is performed alternately in a magnetic field of 3oo0e (Oersted) using a magnetron sputtering device to form a magnetic layer made of iron-silicon magnetic alloy with a thickness of 500A and an intermediate layer made of 5ixNy-niobium-niobium nitride with a thickness of 40A on the substrate. A multilayer film having a total thickness of about 0.8 μm was formed by stacking 15 layers alternately. A crystallized glass (trade name: Photoceram) with a plate thickness of 1.1 rran was used as the substrate.

In addition, the sputtering conditions are as follows: to form an iron-silicon alloy layer, an Ar gas atmosphere is used, and an Ar pressure of 15 mTorr is used.
, input power 12 w7'ct/i s substrate temperature 300
℃, and N was used to form the 5ixNy-Nb-niobium nitride layer.
Using a mixed gas of Ar and N2 containing 26 at%, the gas pressure was 15 mTorr and the input power was 1.9 vil.
The a41 substrate temperature was 300°C.

In Figure 1, the 5ixNy-Nb-niobium nitride intermediate layer contains 1
The graph shows the relationship between the amount of Nb (at%), coercive force, and magnetic permeability. From this, it can be seen that as the amount of Nb contained in the intermediate layer increases, the magnetic permeability increases.

Example 2 A multilayer film was formed in the same manner as in Example 1 except that the ratio of N2 in the mixed gas of Ar and N2 was varied.

FIG. 2 is a graph showing the relationship between the content of N2 (at%) in the mixed gas, coercive force, and magnetic permeability when forming a 5ixNy-Nb-niobium nitride layer.

From this, it can be seen that when the N2 content in the mixed gas is large, both the coercive force and the magnetic permeability are improved.

In Fig. 3, Fe 5sssi 3.4/Si3N4
Multilayer film and Feg6.6 St 3.4/SixN
yNb-niobium nitride multilayer film with respect to each heat treatment temperature, Figure 4 shows the change in coercive force of F'e966Si
3.4/ Si3N4 multilayer film and F'e96-6si3
．． Changes in magnetic permeability (μiac) of the 4/5ixNy-Nb-niobium nitride multilayer film with respect to each heat treatment temperature.

From these results, by adding Nb to the intermediate Si3N4 layer, the heat resistance stability of the soft magnetic characteristics 1 becomes better.

Example 3 Using an iron-silicon alloy target containing 3.4 at% silicon and a composite target in which small pieces of niobium were placed on a silicon dioxide (Si02) target at an atomic ratio of 6.5 at%, an RF magnetron sputtering device was used. Sputtering is performed alternately in a magnetic field of 5oooe (Oersted),
A total film thickness of about 0.8 μm in which 15 magnetic layers made of iron-silicon magnetic alloy with a thickness of 500 A and intermediate layers made of 5iOz-Nb-niobium nitride with a thickness of 40 A are alternately laminated on a substrate.
A multilayer film was formed. A crystallized glass (trade name: Photoceram) with a thickness of 1.11 m was used as the substrate.

In addition, the sputtering conditions were as follows: to form an iron-silicon alloy layer, an Ar gas atmosphere was used, an Ar pressure of 15 mTorr, an input power of s, a substrate temperature of 300°C, and a substrate temperature of 300°C to form a 5iOz-Nb-niobium nitride layer. is N26
Using a mixed gas of Ar and N2 containing at%, the gas pressure was 15 mTorr, and the input power was 1.9 vi/c.
As substrate temperature was set at 300°C.

In FIG. 5, F e g6.6 S i 3-4 /
S i Oz multilayer film and Fe964 Si 3.4/
Figure 6 shows the change in coercive force (Hc) with respect to the heat treatment temperature of the 5iOz-Nb-niobium nitride multilayer film.
96-6Si3-4/5iOZ multilayer film and Feg6-a
5ia-n/5iOz-Nb-Nitride = 1-Magnetic permeability (μiac) of multilayer film for each heat treatment temperature
shows the change in In addition to these, by adding Nb to the intermediate layer 5iOz layer, the heat resistance stability of the soft magnetic characteristics 1 becomes better.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the coercive force and permeability of an example of the multilayer ferromagnetic material of the present invention and the Nb content contained in the intermediate layer. Figure 3 is a graph showing the relationship between the coercive force and permeability of an example of the N2 content in the mixed gas at the time of creating the intermediate layer. FIG. 4 is a graph showing changes in coercive force. FIG. 4 is a graph showing changes in magnetic permeability with respect to heat treatment temperature for an example of the multilayer ferromagnetic material of the present invention. FIG. 5 is an example of the multilayer ferromagnetic material of the present invention. FIG. 6 is a graph showing the change in coercive force with respect to the heat treatment temperature of the multilayer ferromagnetic material of the present invention.
It is a graph showing the change in magnetic permeability with respect to the heat treatment temperature in an example. Nb1 (dj''A) Place the whetstone on the shoulder of middle a1,
! The relationship between ai and 1000 is the N2 content (α) in the mixed gas (Ai+A/z).
t"z,) Refining treatment temperature ('C) Temperature treatment temperature (°C) i! Temperature treatment temperature (°C)
C)

Claims (1)

[Claims] In a multilayer film in which iron-based ferromagnetic material layers and nonmagnetic intermediate layers are alternately laminated on a substrate, the nonmagnetic intermediate layer is (a) at least one selected from silicon nitrides and oxides. (
(1) A multilayer ferromagnetic material characterized by containing at least one species of either Nb or niobium nitride.