JPH06101000A - Mr element material and its production - Google Patents

Abstract

PURPOSE:To obtain an MR element material reduced in variance by incorporating a metallic non-ferromagnetic phase between the fine ferromagnetic crystal grains at least partly. CONSTITUTION:At least 30% of the structure of the MR element material consists of the fine ferromagnetic crystal grains having <=500Angstrom diameter. A metallic non-ferromagnetic phase is incoporated between the ferromagnetic crystal grains at least partly, and the ferromagnetic crystal grain is surrounded by the metallic non-ferromagnetic phase. The metallic non-ferromagnetic phase contains at least one element selected from Cu, Cr, Mn, Au, Ag and Ru, and the fine ferromagnetic crystal grain contains at least one element selected from Fe, Co and Ni. An MR element material appropriate for the magnetic sensor, magnetic head, etc., is obtained in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MR element material suitable for magnetic sensors, magnetic heads and the like.

[0002]

2. Description of the Related Art M utilizing the magnetoresistive effect (MR effect)
Permalloy having a composition mainly of 80 wt% Ni is currently used for the R sensor and the MR head. A thin film produced by sputtering or vapor deposition is usually used for the MR sensor and the MR head. The magnetoresistive effect (MR effect) is one of the current magnetic effects and is a phenomenon in which the resistivity ρ changes when a magnetic field H is applied to the sample. The change Δρ of ρ is generally related to the angle between the resistance measuring current i and H and the magnitude of H. The magnetoresistive effect is usually defined by Δρ / ρ,
Particularly, when i and H are parallel to each other, it is called a magnetoresistive longitudinal effect, and when i and H are at a right angle, it is called a magnetoresistive lateral effect. When the external magnetic field H is applied in the hard axis direction, the electric resistance changes due to the magnetization rotation. The resistance at this time is expressed as R = R ₀ −ΔR sin ² θ. Here, R is the resistance of the element, R ₀ is the resistance of the element when the magnetization M is aligned in the easy axis of magnetization, θ is the angle formed by the magnetization vector M and the current vector I, and Δ
R is an anisotropic magnetoresistance. FIG. 1 shows an example of the ΔR / RH curve when H is added perpendicularly to the i direction. A material having a large resistance change rate Δρ _m / ρ ₀ is required as a material for the MR element. However, in order to perform stable operation, the coercive force is small, the magnetic permeability is high, the magnetostriction constant is small, and the temperature coefficient of the resistivity is small. Smallness is also important. ΔR / R of permalloy thin film is about 2-3% at room temperature, and maximum of NiCo alloy is about 6%.
MR effect of is reported. Recently, it has been clarified that the Fe / Cr artificial lattice multilayer film and the Fe-Ni / Cu / Co artificial lattice multilayer film show a large MR effect. This is called the giant magnetoresistive effect at present, in distinction from the usual magnetoresistive effect. It is considered that the giant magnetoresistive effect essentially increases the effect when the magnetizations of the adjacent magnetic layers of the multilayer film are antiparallel.

[0003]

However, in the permalloy film, ΔR / R is at most 2 to 3% at room temperature, and practical use is possible, but it cannot be said to be sufficient sensitivity for high density recording. . The NiCo alloy film has a problem that the anisotropic magnetic field is large. Further, in the artificial lattice multilayer film, it is necessary to form films of several ⇔ to several tens of ⇔ between the magnetic layers, and it is difficult to control the film thickness, the film interface is easily disturbed, and the reproducibility of characteristics is poor. Further, if the temperature of the substrate rises, this problem is likely to occur, and there is a limit to the speed of film formation.

[0004]

In order to solve the above problems, the inventors of the present invention have proposed a metallurgical method in which a film or a ribbon is forcibly alloyed by increasing the cooling rate and then heat-treated. We have found a high-performance MR element material with less variation in characteristics than an MR material such as an artificial lattice multilayer film by using. That is, the present invention is characterized in that at least 30% of the structure consists of fine ferromagnetic crystal grains of 500 angstroms or less, and a metal non-ferromagnetic phase exists in at least a part between the ferromagnetic crystal grains. It was found that the above materials are excellent as MR element materials, high ΔR / R is obtained, and the reproducibility of characteristics is excellent as compared with the artificial lattice multilayer film. In particular, a high ΔR / R is obtained when the metal non-ferromagnetic phase exists so as to surround the periphery of the ferromagnetic crystal grains. The alloy material of the present invention has excellent reproducibility of characteristics as compared with the artificial lattice multilayer film. Examples of the non-ferromagnetic phase include antiferromagnetic phase. At least 30% of the tissue in the present invention
Is required to be a fine ferromagnetic crystal grain of 500 angstroms or less. This is because if it is less than 30%, a large ΔR / R cannot be obtained, and if it exceeds 500 angstroms, the soft magnetic properties deteriorate and it becomes impractical. Metal non-ferromagnetic phase
In many cases, particularly high ΔR / R is obtained when at least one element selected from Cu, Cr, Mn, Au, Ag, and Ru is contained.
Fine ferromagnetic crystal grains are at least selected from Fe, Co and Ni
Contains one element. The typical composition of the material of the present invention is represented by the composition formula: M _{100-x X'x} (at%), where M is Fe, C.
At least one element selected from o and Ni, X'is Cu, Cr, M
n, Au, Ag, at least one element selected from Ru,
A composition represented by 0¬x≤70 is mentioned. A high ΔR / R is obtained in this range. Further, the composition _{formula: M 100-xa X 'x} M'a
(at%), M is at least one element selected from Fe, Co, Ni, M'is at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Mo, W Element, X'is at least one element selected from Cu, Cr, Mn, Au, Ag, Ru, 0 ¬ x ≤ 70, a
The composition represented by ≦ 20 and a + x ≦ 70 also shows high ΔR / R.
Further, the composition formula: represented by _{M 100-xaz X 'x M'aX} z (at%),
Here, M is at least one element selected from Fe, Co, Ni, M'is at least one element selected from Ti, Zr, Hf, V, Nb, Ta, Mo, W, X'is Cu, Cr , Mn, Au, Ag, at least one element selected from Ru, X is at least one element selected from Si, B, P, C, Ga, Al, 0 ¬ x ≦ 70, a ≦ 2
A high ΔR / R represented by 0, z ≦ 30, and a + x + z ≦ 70 can be obtained. In the present invention, the thickness of the non-magnetic phase is usually a number
From a few hundred ⇔. Also, this non-magnetic phase does not have to completely surround the ferromagnetic crystal grains. Further, the material of the present invention may be formed into a multilayer film if necessary. As the film sandwiched between the layers, a non-ferromagnetic film such as Cu, Ag, and Au is more desirable, and a film that is hard to form a solid solution with a ferromagnetic element is more suitable. The magnetostriction of the ferromagnetic phase is more preferably close to zero. The material of the present invention is usually manufactured as follows. The process of producing an amorphous or fine crystal grain ribbon in which the constituent elements are solid-solved by the liquid quenching method, and at least 30% or more of the structure consists of fine ferromagnetic crystal grains of 500 angstroms or less, and the ferromagnetic crystal grains A manufacturing method consisting of a step of heat-treating so that a metal non-ferromagnetic phase exists in at least a part of the space, a step of manufacturing a film composed of amorphous or fine crystal grains in which the constituent elements are solid-solved by a vapor phase quenching method, and a structure At least 30% or more of 500 angstroms or less consisting of fine ferromagnetic crystal grains, and a manufacturing method comprising a step of heat treatment so that a metal non-ferromagnetic phase exists in at least a part between the ferromagnetic crystal grains, The process of producing a film consisting of amorphous or fine crystal grains in which the constituent elements are solid-solved by the plating method, and at least 30% or more of the structure has a fineness of 500 angstroms or less. MR to Do a ferromagnetic crystal grains, and characterized by comprising the step of heat treating such that the metal non-ferromagnetic phase is present in at least a portion between the ferromagnetic crystal grains
There is a method of manufacturing a device material. In the present invention, in the state before the heat treatment, it is possible to obtain a preferable result in which the constituent elements are completely in solid solution with less variation, but it is possible to obtain the effect of the present invention even if not completely dissolved. Included in the invention. The heat treatment also includes the purpose of crystallization when the heat treatment is in an amorphous state. Further, the metal non-ferromagnetic phase between the ferromagnetic crystal grains may be an amorphous phase. Further, the ferromagnetic phase does not have to be one phase, and two or more phases may exist.

[0005]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. (Example 1) An amorphous alloy ribbon having a composition of Fe _bal. Cu ₁₀ Nb ₃ Si _13.5 B ₉ was produced by a single roll method. Next, this alloy ribbon was heat-treated at 550 ° C. The obtained alloy was crystallized as a result of microstructure observation, and most of the structure was composed of fine crystal grains with a grain size of 500 or less. Further, the non-ferromagnetic phase is formed around the formed ferromagnetic crystal grains by the electron diffraction, the Mossbauer effect, and the ED.
Confirmed by compositional analysis by X. A schematic diagram of the structure of the obtained alloy is shown in FIG. The structure is such that the non-magnetic phase surrounds the ferromagnetic bcc crystal grains. It was confirmed that Cu was considerably contained in the non-ferromagnetic phase, and it was confirmed to be non-magnetic. The DC BH curve is shown in FIG. B-
The H curve has a bend and a characteristic hysteresis rule
Shows the Next, the variation of the maximum value ΔR _m / R of ΔR / R obtained by the MR effect measurement of 20 samples was 9%, and Co (6
It was confirmed that it was significantly smaller than 57% of the artificial lattice multilayer film of ⇔) / Ag (25⇔) and was excellent in reproducibility. In addition, ΔR _m / R
When the average value of ΔR _m / R is a, the maximum value is m, and the minimum value is s, the variation is defined as (ms) × 100 / a. Example 2 An alloy film having the composition (at%) shown in Table 1 was formed by the sputtering method, and then heat-treated at 650 ° C. for 1 hour. As a result of microstructure observation, most of the structure of the alloy film was composed of fine crystal grains with a grain size of 500 or less. Further, the non-ferromagnetic phase is formed around the formed ferromagnetic crystal grains by the electron diffraction, the Mossbauer effect, and the ED.
Confirmed by compositional analysis by X. Next, the magnetoresistive curve of this alloy film was measured. ΔR / R obtained by measurement
Table 1 shows the average ΔR _m / R of the maximum values and the variation (%) of ΔR _m / R when 20 samples were prepared.

[Table 1] (Example 3) An amorphous alloy film having the composition shown in Table 2 was formed by a sputtering method, and then heat-treated at 650 ° C for 1 hour to be crystallized. As a result of microstructure observation, the alloy film was crystallized and most of the structure was composed of fine crystal grains with a grain size of 500 or less. Further, it was confirmed by electron beam diffraction, Mossbauer effect, and composition analysis by EDX that a non-ferromagnetic phase was formed around the formed ferromagnetic crystal grains. Next, the magnetoresistive curve of this alloy film was measured. Maximum average value of ΔR / R obtained by measuring 20 samples
The variation (%) of R _m / R is shown in Table 2.

[Table 2]

[0006]

According to the present invention, a high ΔR / R suitable for a magnetic sensor, a magnetic head and the like can be obtained and a material for an MR element having a small variation can be obtained, and the effect is remarkable.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a ΔR / RH curve when H is added perpendicularly to the i direction.

FIG. 2 is a schematic diagram showing an example of a structure of an alloy according to the present invention.

FIG. 3 is a diagram showing an example of a DC BH curve according to the present invention.

Claims (9)

[Claims] 1. At least 30% or more of the structure is composed of fine ferromagnetic crystal grains of 500 angstroms or less, and a metal nonferromagnetic phase exists in at least a part between the ferromagnetic crystal grains. Characteristic material for MR element. 2. The MR element material according to claim 1, wherein the metallic non-ferromagnetic phase exists so as to surround the periphery of the ferromagnetic crystal grains. 3. The MR element according to claim 1, wherein the metallic non-ferromagnetic phase contains at least one element selected from Cu, Cr, Mn, Au, Ag and Ru. material. 4. The MR element material according to claim 1, wherein the fine ferromagnetic crystal grains contain at least one element selected from Fe, Co and Ni. 5. A composition formula: M _{100-x X'x} (at%), wherein M is at least one element selected from Fe, Co and Ni,
X'is at least one element selected from Cu, Cr, Mn, Au, Ag, Ru, and 0 ≤ x ≤ 70, wherein
To the MR element material according to claim 4. 6. The composition formula: 'is represented by _x M'a (at%), where at least one element M is Fe, Co, chosen from _{Ni, M' M 100-xa} X is Ti, Zr, Hf, V, Nb, Ta, Mo, at least one element selected from W, X'is at least one element selected from Cu, Cr, Mn, Au, Ag, Ru, 0¬x ≦ 70 , A ≦ 20, a + x ≦
70. The MR element material according to claim 1, wherein the material is 70. 7. A composition formula: 'is represented by _x M'aX _z (at%), wherein M is at least one element selected Fe, Co, from _{Ni, M' M 100-xaz} X is Ti, Zr , Hf, V, Nb, Ta, Mo, at least one element selected from W, X'is at least one element selected from Cu, Cr, Mn, Au, Ag, Ru, X is Si, B, P, C, Ga, Al
At least one element selected from 0 ¬ x ≦ 70,
The MR element material according to claim 1, wherein a ≦ 20, z ≦ 30, and a + x + z ≦ 70. 8. A step of producing an amorphous or fine crystal grain ribbon in which constituent elements are solid-solved by a liquid quenching method,
At least 30% or more of the structure is composed of fine ferromagnetic crystal grains of 500 angstroms or less, and the heat treatment is performed so that the metal non-ferromagnetic phase exists in at least a part of the ferromagnetic crystal grains. A method for producing a material for an MR element, which is characterized. 9. A process for producing a film composed of amorphous or fine crystal grains in which constituent elements are solid-solved by a vapor phase quenching method, and at least 30% or more of the structure is formed from fine ferromagnetic crystal grains of 500 Å or less. And a heat treatment step such that a metal non-ferromagnetic phase exists in at least a part of the ferromagnetic crystal grains.