JPH0744809A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To provide magnetic head of high output by holding a magnetic core from its both sides and providing the core with a pair of reinforcing bodies having through- holes for regulating the depth of a gap. CONSTITUTION:This magnetic head has the magnetic core 1 which consists of a magnetic metallic material provided with a gap 6 having a prescribed depth on a surface facing a recording medium and a through-hole 3 for regulating the depth of this gap 6 and a pair of the reinforcing bodies 2a, 2b which hold the core 1 from both side. The reinforcing bodies 2a, 2b having coefft. of thermal expansion larger than the coefft. of thermal expansion of the soft magnetic metallic material are used when the saturation magnetic strain of the soft magnetic metallic material forming the magnetic core 1 is positive. The reinforcing bodies 2a, 2b having a coefft. of thermal expansion smaller than the coefft. of thermal expansion of the soft magnetic metallic material are used when the saturation magnetic strain of the soft magnetic metallic material is negative. The magnetic path direction of magnetic fluxes 33 introduced from the gap 34 (6) into the magnetic core 1 is the direction of the axis of difficult magnetization in the magnetic domain structure thereof and, therefore, the magnetic fluxes are passed in the core with good efficiency even for high frequency and the higher output is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head, and more particularly to a magnetic head using a metal soft magnetic material as a magnetic core for high density recording / reproduction.

[0002]

2. Description of the Related Art With the increasing density of magnetic recording, a large coercive force is required for a recording medium and a large saturation magnetization is required for a magnetic head corresponding to a medium having a large coercive force. Metal soft magnetic materials (eg sendust,
Amorphous) has a higher saturation magnetic flux density than conventional ferrite, so magnetic heads using this as a magnetic core have been developed.

FIG. 1 shows a typical example of the above magnetic head. The magnetic head comprises a magnetic core 1 and reinforcing bodies 2a and 2b sandwiching the magnetic core from both sides thereof, and a coil 4 is formed by utilizing a winding window 3. Here, the magnetic head having this structure is generically referred to as a laminated head.

In this laminated magnetic head, a head using a sendust sputtered film (FeSiAl alloy or an alloy in which Cr, Ru, Ti or the like is added to FeSiAl) as a magnetic core has been developed (issued in October 1991). Proceedings of the 15th Annual Meeting of the Applied Magnetics Society of Japan, p.
10). Furthermore, a FeNM sputtered film (M is T) having a large saturation magnetization of sendust (saturation magnetization of about 10 kG) or more.
a, Zr, Nb, Hf, at least one kind of element selected from among Ti, when represented by a composition of _{Fe x M y N z, x} , y, when the the atomic% z, 70.5 ≦ x ≦
84, 7 ≦ y ≦ 14, 9 ≦ z ≦ 15.5 range: Japanese Patent Application No. 2-023686) or FeNML sputtered film (M is at least selected from Ta, Zr, Nb, Hf and Ti). One element, L is Cu and / or A
g, and when expressed by a composition of _{(Fe x M y N z)} a L b, x, y, z, a, when b is referred to as atomic%, 70.5 ≦
x ≦ 84, 7 ≦ y ≦ 14, 9 ≦ z ≦ 15.5, 95 ≦ a
Range of ≦ 99.5, 0.5 ≦ b ≦ 5: Japanese Patent Application No. 2-104
952) was invented, and a head using a sputtered film (saturation magnetization of 15 kG or more) containing Fe, Ta, and N as the main components is also being developed (15th Japan Society for Applied Magnetics, published in October 1991). Academic Lecture Summary, p.11). However, the magnetic head using this FeTaN film leaves room for improvement in the magnetic characteristics of the magnetic core and the like. That is, the magnetic domain structure of the magnetic core is not optimized so as to improve the reproduction efficiency under the present circumstances.

An object of the present invention is to solve such conventional problems.

[0006]

The present invention comprises a metal soft magnetic material having a gap having a predetermined depth on a surface facing a recording medium, and a through hole defining the depth of the gap. In a magnetic head comprising a magnetic core and a pair of reinforcing bodies sandwiching the magnetic core from both sides thereof and having a through hole matching the through hole, when the saturation magnetostriction of the metal soft magnetic material is positive, the heat of the reinforcing body is increased. The expansion coefficient is larger than the thermal expansion coefficient of the metal soft magnetic material, and when the saturation magnetostriction of the metal soft magnetic material is negative, the thermal expansion coefficient of the reinforcing body is smaller than that of the metal soft magnetic material. It is a magnetic head.

[0007]

FIG. 3 shows an example of the magnetic domain structure of the magnetic core of the laminated head. Magnetic flux 3 introduced into the core from the gap 34
Since the magnetic path direction of 3 is in the hard axis direction due to the magnetic domain structure shown by 32, it can efficiently pass through the core even at high frequencies. On the other hand, in the case of the magnetic domain structure shown in FIG. 4, the magnetic path direction is the direction of the easy axis of magnetization, and therefore the efficiency at high frequencies is reduced. Therefore, a highly efficient stacked head can be obtained by the magnetic domain structure of FIG.

In order to realize the magnetic domain structure shown in FIG. 3,
The stress-induced anisotropy via the magnetostriction and stress of the magnetic core may be controlled. That is, by making the magnetostriction negative when the tensile force is generated in the magnetic core, or by making the magnetostriction positive when the compressive force is generated, the outer peripheral portion of the magnetic core or the winding window peripheral portion, That is, in the portion where the stress is released in the normal direction, the normal direction becomes the easy axis of magnetization, and the magnetic domain shown in FIG. 3 is formed. With this magnetic domain structure, a laminated head having high reproduction efficiency can be obtained.

The saturation magnetostriction of the FeNM film and the FeMNL film is controlled by the nitrogen composition in the film and the heat treatment conditions. Also,
The stress is controlled by the coefficient of thermal expansion of the substrate.

Fe, N, M (M is Ta, Zr, Nb, H
(at least one element selected from f and Ti)
In the alloy film containing as a main component, Ta was used as M, and a FeTaN film was formed to a thickness of about 3 μm on a ceramic or glass substrate by a magnetron sputtering method. As a target, a composite type in which a Ta chip is arranged on a Fe plate or an alloy type of FeTa is used, and nitrogen is supplied from an atmosphere gas during film formation, and the concentration in the film is changed by changing the nitrogen pressure. It was After the deposition, 1 × 10 ^{- 5} To
Heat treatment at 550 ° C for 1 hour in a vacuum of rr or less,
Then, the saturation magnetostriction (λs) was measured in the rotating magnetic field in the film plane. FIG. 5 shows the composition dependence of λs. Coercive force (H
In the composition region suitable as a head material where c) is 10e or less, λs varied from positive to negative depending on the composition of nitrogen. That is, λs could be controlled by the nitrogen composition. FIG. 6 is a diagram showing the heat treatment temperature dependence of λs of the FeTaN film. With increasing heat treatment temperature, λs changed from positive to negative even with the same composition. Λs could be controlled also by the heat treatment temperature.

FIG. 7 shows the temperature dependence of the internal stress of the FeTaN film formed on the substrates having different thermal expansion coefficients (α). α is 35 × 10 ^{- 7} substrate is a single crystal became parallel to the surface (100) plane of Si, 136 × 10 ^- substrate ⁷ is a ceramic whose main component NiO, CaO, and TiO ₂ . The slopes of the straight lines in the figure are the substrate and F
It is determined by the difference in the coefficient of thermal expansion from the eTaN film.
When the thermal expansion coefficient of the FeTaN film is calculated from FIG. 7, it is 112 ×
^10-7 was obtained. Using this value, the stress of the FeTaN film when the thermal expansion coefficient of the substrate is changed is set to the heat treatment temperature 550.
The calculation results for the case of ° C are shown in Fig. 8. It is clear from FIG. 8 that the stress of the FeTaN film can be controlled by the thermal expansion coefficient of the substrate.

By controlling the saturation magnetostriction and stress as described above, F
By making the stress of the eTaN film a tensile force and making the magnetostriction negative, and making the stress a compressive force and making the magnetostriction positive, the magnetic domains shown in FIG. 3 were formed in the magnetic core. vice versa,
By making the stress of the FeTaN film a tensile force and making the magnetostriction positive, and making the stress a compressive force and making the magnetostriction negative, the magnetic domains shown in FIG. 4 were formed in the magnetic core.

[0013]

EXAMPLES Next, examples of the present invention will be described.

In the laminated head shown in FIG. 1, four layers of a FeTaN film having a thickness of 3 μm are laminated as a magnetic core film through an alumina intermediate layer film having a thickness of 0.1 μm, and NiO, CaO, and TiO are used as a reinforcing member. _{ceramics 2} as a main component (coefficient of thermal expansion 136 × 10 ^{- 7),} and, Ca
Ceramics mainly composed of O and TiO ₂ (coefficient of thermal expansion 1
05 × 10 ^{- 7)} was used to prepare a multilayer head with a gap length 0.2 [mu] m. The saturation magnetostriction of the FeTaN film was performed by changing the nitrogen pressure during film formation to control the nitrogen composition in the film. The film formation is performed by a DC magnetron sputtering method, a mixed gas of argon and nitrogen is used as an atmospheric gas, the total pressure is 3 mTorr, and the nitrogen pressure is 0.2 mTorr.
It was changed from r to 0.3 mTorr.

[0015] forming a film of the composition shown in FIG. _6, Fe ₇ 6 _.0 Ta ₈ by a heat treatment at 550 ° _{C.. 5} N
_{1 5.5} film with a positive magnetostriction _{(at%), Fe 7 7} . 8 Ta
_{8. 2} N _{1 4. 0} to give a negative magnetostriction film (at%). Both saturation magnetizations were 15 kG to 16 kG.
Positive magnetostriction of the film and NiO, CaO, ceramic substrate mainly composed of TiO ₂ (thermal expansion coefficient of 136 × 10 ^{- 7)} the ceramic substrate mainly composed combination, or negative magnetostrictive film and CaO, of TiO ₂ and ( Thermal expansion coefficient 105 × 10
^-7 ) in combination with the head having the magnetic domain structure shown in FIG. 3, and a positive magnetostrictive film and a ceramic substrate mainly composed of CaO and TiO ₂ (coefficient of thermal expansion 105 × 10 5
^- combination of ⁷⁾ or negative magnetostrictive film and NiO,,
CaO, ceramic substrate mainly composed of TiO ₂ (thermal expansion coefficient of 136 × 10 ^{- 7)} In combination with, FIG. 4
A head having a magnetic domain structure shown in FIG.

FIG. 9 shows the recording density characteristics of the reproduction output of the magnetic domain structure laminated head shown in FIG. 3 and the magnetic domain structure head shown in FIG. Coercive force of 15 as magnetic tape
A metal tape of 00 (Oe) was used, and the relative speed between the head and the tape was 21.4 m / sec. A high output was obtained by the laminated head having the magnetic domain structure of FIG.

The above results show that FeTaN film is Fe _x M _y N
_When expressed by the composition of _z , if x, y, and z are atomic%,
70.5 ≦ x ≦ 84, 7 ≦ y ≦ 14, 9 ≦ z ≦ 15.5
The same applies if the composition range is In the FeMN film,
Similarly, when Zr, Hf, Ti or Nb other than Ta is used, the magnetostriction can be controlled by the nitrogen composition and the heat treatment condition, and the stress can be controlled by the thermal expansion coefficient of the substrate.

When FeNML film is used as the magnetic core material, when expressed by the composition of (Fe _x M _y N _z ) _a L _b , x, y, z, a, and b are atomic%, 70.5
≦ x ≦ 84, 7 ≦ y ≦ 14, 9 ≦ z ≦ 15.5, 95 ≦
The same applies if the composition range is a ≦ 99.5 and 0.5 ≦ b ≦ 5.

Although the magnetic head for magnetic tape has been described in the embodiments of the present invention, it goes without saying that the present invention is also applied to a magnetic head for hard disk. Even if the structure of the magnetic head is as shown in FIG. 2, the same result as in the case of FIG. 1 is obtained.

[0020]

As described above, according to the present invention, the laminated head having the magnetic domain structure shown in FIG. 3 is obtained, and high output is realized.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a laminated magnetic head.

FIG. 2 is a perspective view of another example of a laminated magnetic head.

FIG. 3 is an explanatory diagram of an example of a magnetic domain structure of a magnetic core of a laminated magnetic head.

FIG. 4 is an explanatory diagram of another example of the magnetic domain structure of the magnetic core of the laminated magnetic head.

FIG. 5 is a diagram showing composition dependence of saturation magnetostriction (λs) and coercive force (Hc) after heat treatment of a FeTaN sputtered film at 550 ° C. for 1 hour.

FIG. 6 is a diagram showing the heat treatment temperature dependence of the saturation magnetostriction of the FeTaN film.

FIG. 7 is a diagram showing temperature dependence of stress in the FeTaN film.

FIG. 8 is a diagram showing the substrate thermal expansion coefficient dependence of the stress of the FeTaN film.

9 is a diagram showing recording density characteristics of reproduction output of the laminated head having the magnetic domain structure of FIG. 3 and the laminated head having the magnetic domain structure of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 magnetic core 2a, 2b reinforcement body 3 winding window 4 coil 5 glass bonding layer 6,34,44 gap 7,8 bonding glass 31,41 magnetic core 32,42 domain wall 33,43 magnetic flux

Claims (6)

[Claims] 1. A magnetic core made of a soft metal magnetic material having a gap having a predetermined depth on a surface facing a recording medium, and a through hole defining the depth of the gap, and the magnetic core. In a magnetic head composed of a pair of reinforcing bodies sandwiched from both sides thereof and having a through hole matching the through hole, when the saturation magnetostriction of the metal soft magnetic material is positive, the coefficient of thermal expansion of the reinforcement is set to that of the metal soft magnetic material. A magnetic head having a coefficient of thermal expansion larger than that of the metal soft magnetic material and a coefficient of thermal expansion of the reinforcing body being smaller than that of the metal soft magnetic material when the saturation magnetostriction of the metal soft magnetic material is negative. 2. The metal soft magnetic material is Fe, N and M.
(M is Ta, Zr, Nb, Hf, at least one element selected from among Ti) is an alloy mainly comprising, when expressed with the composition of _{Fe x M y N z, x} , y, When z is atomic%, 70.5 ≦ x ≦ 84, 7 ≦ y ≦ 14,
The magnetic head according to claim 1, wherein the range is 9≤z≤15.5. 3. The soft magnetic metal material comprises Fe, N, M (M
A is Ta, Zr, Nb, Hf, at least one element selected from among Ti) and L (alloy L is mainly composed of Cu and / or Ag) and, (Fe _x M _y N
_z ) _a L _b , where x, y, z, a, and b are atomic%, 70.5 ≦ x ≦ 84, 7 ≦ y ≦ 14,
9 ≦ z ≦ 15.5, 95 ≦ a ≦ 99.5, 0.5 ≦ b ≦
The magnetic head according to claim 1, wherein the magnetic head has a range of 5. Wherein said soft magnetic metal material is FeTaN alloy, the thermal expansion coefficient of the reinforcing member when the saturation magnetostriction of the alloy is negative 112 × 10 ^- and ⁷ below, when the saturation magnetostriction is positive The coefficient of thermal expansion of the reinforcement is 112
× 10 ^{- 7} or a magnetic head according to claim 2, characterized in that. The magnetic head according to claim 4, wherein the ⁷ following reinforcement is a ceramic mainly composed of the CaO and TiO ₂ ^- 5. A thermal expansion coefficient of 112 × 10. 6. The method of manufacturing a magnetic head according to claim 1, wherein the metal soft magnetic material is obtained by subjecting the metal soft magnetic material to heat treatment after forming a thin film, A method of manufacturing a magnetic head, which is controlled by the void composition and / or heat treatment conditions after thin film formation.