JPH04252007A - Magnetic head and magnetic recording and replay apparatus usint the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head suitable for recording and reproducing information with high precision on a high coercive force magnetic recording medium used in a VTR, DAT, FDD, or the like.

0002

2. Description of the Related Art In the field of magnetic recording, high-density recording is progressing by shortening wavelengths, and recording media with high coercive force and high residual magnetic flux density are being developed. In order to respond to shorter wavelengths, the gap length must be reduced in order to reduce gap loss. As the gap length becomes narrower, the head magnetic field applied to the medium becomes weaker, and as mentioned above, the medium has a high coercive force, so it is necessary to significantly improve the recording ability of the head. Furthermore, with a narrow gap length, the head distribution efficiency itself decreases, so ensuring reproduction efficiency is also an important issue. This will be explained in detail using figures. FIG. 16 shows the relationship between head distribution efficiency and gap length. As shown in the figure, when the gap length becomes 0.35 μm or less, the distribution efficiency of the head decreases rapidly. That is, for heads with a gap length of 0.35 μm or less, ensuring reproduction efficiency is a particularly important issue.

At present, magnetic heads using materials such as ferrite, CoNbZr, and FeAlSi, which are the mainstream materials for head cores, have relatively good reproduction efficiency, but their saturation magnetic flux densities are 0.5T, 0.9T, and 0.9T, respectively. 1.1T
Therefore, if the coercive force of the recording medium exceeds 1000 oersteds (for example, a metal tape), recording becomes insufficient.

[0004] Therefore, a highly heat-resistant metallic magnetic film with a saturation magnetic flux density of 1.3 T or higher and containing Fe microcrystalline grains as a main component (for example, the 13th Japanese Society of Applied Magnetics Academic Lecture Abstracts, 25aD
-3 “Fe-M-C (M=Ti, Zr, Hf, V, Nb
, Ta) film crystallization behavior") are being proposed.

[0005]

[Problems to be Solved by the Invention] However, in the above-mentioned prior art, the recording ability on a high coercive force medium is limited to ferrite,
Although it is superior to magnetic heads using materials such as CoNbZr and FeAlSi, there is a problem in that the reproduction efficiency, which is an important item in the basic performance of the head, is considerably inferior (particularly in the high frequency region of 3 MHz or higher).

[0006] The present invention has been made in view of the above points.
The purpose is to provide a magnetic head with excellent recording ability and high reproduction efficiency, which has a core material with a saturation magnetic flux density ≧1.3T or more and a gap length ≦0.35 μm.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a magnetic head having a core material having a saturation magnetic flux density ≧1.3T or more and a gap length ≦0.35 μm. The core has uniaxial anisotropy with the axis of easy magnetization in a desired direction.

[0008] Also, preferably in the present invention, the uniaxial anisotropy of the magnetic core is imparted by heat treatment in a magnetic field.

[0009] Also, preferably in the present invention, the heat treatment in a magnetic field is the first heat treatment step in the head manufacturing process.

[0010] Also, preferably in the present invention, the applied magnetic field in the heat treatment in a magnetic field is greater than or equal to the maximum value of the demagnetizing field in the head shape.

[0011] Also preferably in the present invention, the core material is Fe100-xMx (0≦x≦20, atomic %: M
=Ti, V, Zr, Nb, Mo, Ta, Hf, W, Al
, Si, B, C, Ga, Ge, Co, Ni, Ir, Pt
, Au, Rh, and Ru) containing microcrystalline grains (grain size of 500 Å or less).

[0012] Also preferably in the present invention, the core material has Fe100-x-yCoxMy (0≦x≦40,
0≦y≦20, atomic %: M=Ti, V, Zr, Nb, M
o, Ta, Hf, W, Al, Si, B, C, Ga, Ge
, Ni, Ir, Pt, Au, Rh, and Ru).

[0013] Also preferably in the present invention, the core material is Co100-xMx (0≦x≦20, atomic %: M
=Ti, V, Zr, Nb, Mo, Ta, Hf, W, Al
, Si, B, C, Ga, Ge, Fe, Ni, Ir, Pt
, Au, Rh, and Ru) containing microcrystalline grains (grain size of 500 Å or less).

[0014]

[Effect] The core material, which has uniaxial anisotropy and is heat-treated in a magnetic field in a magnetic field greater than the maximum value of the demagnetizing field in the head shape in the first heat treatment process, improves the head reproduction efficiency in the high frequency region. work.

[0015] For the above reasons, the core material is Fe.
100-xMx (0≦x≦20, atomic %: M=Ti, V
, Zr, Nb, Mo, Ta, Hf, W, Al, Si, B
, C, Ga, Ge, Co, Ni, Ir, Pt, Au, R
microcrystalline grains (grain size 5) containing at least one of h, Ru
00 Å or less) or Fe100-x-
yCoxMy(0≦x≦40, 0≦y≦20, atomic%:
M=Ti, V, Zr, Nb, Mo, Ta, Hf, W, A
l, Si, B, C, Ga, Ge, Ni, Ir, Pt, A
microcrystalline grains (containing at least one of u, Rh, Ru)
magnetic film containing grain size of 500 Å or less) or Co100
-xMx (0≦x≦20, atomic %: M=Ti, V, Zr
, Nb, Mo, Ta, Hf, W, Al, Si, B, C,
Ga, Ge, Fe, Ni, Ir, Pt, Au, Rh, R
microcrystalline grains (grain size 500 Å) containing at least one type of
It is preferable that the magnetic film contains the following:

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows the frequency characteristics of the reproduction output of the magnetic head according to the present invention. As shown in the figure, according to the present invention, the core material has a saturation magnetic flux density ≧1.3T or more, and the gap length ≦
In a magnetic head with a diameter of 0.35 μm, the recording ability in the low frequency range is equal to or higher than that of a conventional magnetic head with a core material mainly composed of Fe microcrystalline grains, and the reproduction efficiency in the high frequency range is equivalent to that of a ferrite head. The above magnetic head can be obtained. The fact that reproduction efficiency in the high frequency region is excellent means that the frequency characteristics of the soft magnetic properties of the magnetic material used for the head core material are excellent. This will be explained in detail below.

FIG. 2 shows the structure of a conventional soft magnetic film mainly composed of Fe microcrystalline grains, FIG. 3 shows its BH curve, and FIG. 4 shows its relative magnetic permeability. The reason Fe exhibits soft magnetic properties despite its large magnetocrystalline anisotropy is that its crystal grains are small (
This is thought to be due to exchange interaction between crystal grains (approximately 500 Å or less). However, as shown in Fig. 3, in the past, although the coercive force was small and soft magnetic properties were obtained, the relative magnetic permeability was so-called Ms2/2K (Ms: saturation magnetization,
K: anisotropic magnetic field), and its frequency characteristics were also inferior. Therefore, we aimed to improve the soft magnetic properties by controlling the magnetic anisotropy using the method detailed below.

FIG. 5 shows Fe100-XMx microcrystalline grains (0≦x≦20, atomic %: M=Ti, V, Zr,
Nb, Mo, Ta, Hf, W, Al, Si, B, C, G
a, Ge, Co, Ni, Ir, Pt, Au, Rh, Ru
FIG. 6 shows its BH curve, and FIG. 7 shows its relative magnetic permeability. A soft magnetic film having uniaxial anisotropy (anisotropic magnetic field: about 320 A/m) was obtained by replacing conventional Fe microcrystalline grains with Fe100-XMx microcrystalline grains and subjecting them to heat treatment in a magnetic field. In addition, its relative magnetic permeability is approximately Ms2/2K (Ms: saturation magnetization, K
: anisotropic magnetic field) and has excellent frequency characteristics. Further, at this time, the magnetostriction constant becomes 5/107 or less. Furthermore, we confirmed the existence of domain walls unique to magnetic materials with uniaxial anisotropy by measuring the magnetic Kerr effect. This will be explained in detail below.

FIG. 8 shows Fe100-XMx microcrystalline grains (0≦x≦20, atomic %: M=Ti, V, Zr,
Nb, Mo, Ta, Hf, W, Al, Si, B, C, G
a, Ge, Co, Ni, Ir, Pt, Au, Rh, Ru
Fig. 9 shows the Kerr effect in the direction of the easy axis of magnetization of a soft magnetic film whose main component is Fe microcrystalline grains. As shown in FIG. 8, the existence of a domain wall was confirmed because the Kerr effect, which is unique when there is domain wall movement, was obtained. This proves that the soft magnetic film according to the present invention has good uniaxial anisotropy. On the other hand, in the conventional soft magnetic film mainly composed of Fe microcrystalline grains, the presence of domain walls was not observed anywhere on the film.

Next, important findings regarding heat treatment in a magnetic field, which is an important element of the present invention, will be described in detail. 10 to 12 are comparisons of BH curve differences due to different heat treatment steps. FIG. 10 shows the BH curve of a soft magnetic film subjected to heat treatment in a magnetic field according to the present invention, and FIGS. 11 and 12 show BH curves of soft magnetic films in which good uniaxial anisotropy was not obtained. In particular, as shown in FIG. 11, it has been found that once heat treatment is performed in a non-magnetic field, it is difficult to obtain good uniaxial anisotropy even if heat treatment is performed in a magnetic field thereafter. Further, good uniaxial anisotropy could not be obtained even if heat treatment was performed in a non-magnetic field after sputtering in a magnetic field. That is, it is important for obtaining good uniaxial anisotropy that the first heat treatment step is heat treatment in a magnetic field as in the present invention. Of course, it is obvious that it is important that the first heat treatment step in the head manufacturing process is heat treatment in a magnetic field. At this time, even if this step is a glass bonding step, glass bonding may be performed in a magnetic field. In this way, the activation energy of soft magnetic materials mainly composed of microcrystalline grains is larger than that of amorphous materials, whose magnetic anisotropy can be controlled relatively easily. Medium heat treatment is required.
extremely important.

Furthermore, important findings regarding the applied magnetic field have been obtained, which will be described in detail. FIG. 17 shows the relationship between applied magnetic field strength and reproduction output. As is clear from the figure, it is desirable that the applied magnetic field is equal to or greater than the maximum value of the demagnetizing field in the head shape.

Next, other embodiments of the present invention will be described. Figure 1
3 is Fe100-x-yCoxMy microcrystalline grain according to the present invention (0≦x≦40, 0≦y≦20, atomic %: M=Ti,
V, Zr, Nb, Mo, Ta, Hf, W, Al, Si,
B, C, Ga, Ge, Ni, Ir, Pt, Au, Rh,
FIG. 14 shows its BH curve, and FIG. 15 shows its relative magnetic permeability. As described above, according to the present invention, even better uniaxial anisotropy can be obtained.

[0024]

Effects of the Invention As described above, according to the present invention, the core material has a saturation magnetic flux density ≧1.3T or more, and the gap length ≦0.35μ.
Controlling the magnetic anisotropy of the soft magnetic film, which is the core material of the magnetic head, in the magnetic head having a The effect is that the reproduction efficiency in the high frequency region is equal to or higher than that of a magnetic head and equal to or higher than that of a ferrite head.

[Brief explanation of the drawing]

[Fig. 1] Frequency characteristic diagram of reproduction output of the magnetic head according to the present invention

[Figure 2] Structural diagram of a conventional soft magnetic film mainly composed of Fe microcrystalline grains

[Figure 3] BH curve characteristic diagram of a conventional soft magnetic film mainly composed of Fe microcrystalline grains

[Fig. 4] A diagram showing the relative magnetic permeability of a conventional soft magnetic film mainly composed of Fe microcrystalline grains.

[Fig. 5] Structural diagram of a soft magnetic film mainly composed of Fe100-XMx microcrystal grains according to the present invention

[Fig. 6] BH curve characteristic diagram of the soft magnetic film mainly composed of Fe100-XMx microcrystalline grains according to the present invention

FIG. 7 is a diagram showing the relative magnetic permeability of a soft magnetic film mainly composed of Fe100-XMx microcrystalline grains according to the present invention.

FIG. 8 is a diagram showing the Kerr effect in the easy axis direction of the soft magnetic film mainly composed of Fe100-XMx microcrystalline grains according to the present invention.

[Fig. 9] A diagram showing the Kerr effect of a conventional soft magnetic film mainly composed of Fe microcrystalline grains.

[Figure 10] BH curve characteristic diagram due to the heat treatment process according to the present invention

[Figure 11] BH curve characteristic diagram due to heat treatment process according to reference example

[Figure 12] BH curve characteristic diagram due to heat treatment process according to reference example

FIG. 13: Fe100-x-yCoxMy according to the present invention
Structural diagram of a soft magnetic film whose main component is microcrystalline grains

FIG. 14: Fe100-x-yCoxMy according to the present invention
BH curve characteristic diagram of soft magnetic film mainly composed of microcrystalline grains

[
FIG. 15 is a diagram showing the relative magnetic permeability of a soft magnetic film mainly composed of Fe100-x-yCoxMy microcrystalline grains according to the present invention.

[Figure 16] Diagram showing the relationship between head distribution efficiency and gap length

[Figure 17] Diagram showing the relationship between applied magnetic field strength and reproduction output

[Explanation of symbols]

1. ．． ．． Domain wall, 2. ．． ．． Fe microcrystalline grains, 3. ．．
．． Magnetic moment of Fe microcrystalline grains, 4. ．． ．． Other crystal grains, 5. ．． ．． Fe100-XMx microcrystalline grains,
6. ．． ．． Magnetic moment of Fe100-XMx microcrystalline grains, 7. ．． ．． Fe100-x-yCoxMy microcrystalline grains, 8. ．． ．． Magnetic moment of Fe100-x-yCoxMy microcrystalline grains

Claims (8)

[Claims] Claim 1: A magnetic head having a core material with a saturation magnetic flux density ≧1.3T and a gap length ≦0.35 μm, in which the magnetic core of the magnetic head has uniaxial anisotropy with a desired direction as the axis of easy magnetization. magnetic head. 2. The magnetic head according to claim 1, wherein the uniaxial anisotropy of the magnetic core is imparted by heat treatment in a magnetic field. 3. The magnetic head according to claim 1, wherein the heat treatment in a magnetic field is the first heat treatment step in a head manufacturing process. 4. The magnetic head according to claim 1, wherein the applied magnetic field in the magnetic field heat treatment is greater than or equal to the maximum value of the demagnetizing field in the head shape. 5. The core material is Fe100-xMx (0≦
x≦20, atomic %: M=Ti, V, Zr, Nb, Mo,
Ta, Hf, W, Al, Si, B, C, Ga, Ge, C
Claim 1, 2, 3, or 4, characterized in that the magnetic film is a magnetic film containing microcrystalline grains (grain size of 500 Å or less) containing at least one of O, Ni, Ir, Pt, Au, Rh, and Ru.
The magnetic head described in . 6. The core material is Fe100-x-yCox
My(0≦x≦40, 0≦y≦20, atomic %: M=Ti
, V, Zr, Nb, Mo, Ta, Hf, W, Al, Si
, B, C, Ga, Ge, Ni, Ir, Pt, Au, Rh
, Ru) microcrystalline grains (grain size 50
5. The magnetic head according to claim 1, wherein the magnetic head is a magnetic film containing a magnetic film having a thickness of 0 Å or less. 7. The core material is Co100-xMx (0≦
x≦20, atomic %: M=Ti, V, Zr, Nb, Mo,
Ta, Hf, W, Al, Si, B, C, Ga, Ge, F
Claim 1, 2, 3, or 4, characterized in that the magnetic film is a magnetic film containing microcrystalline grains (grain size of 500 Å or less) containing at least one of e, Ni, Ir, Pt, Au, Rh, and Ru.
The magnetic head described in . 8. A magnetic recording and reproducing apparatus using the magnetic head according to claim 1, 2, 3, 4, 5, 6, or 7.