JPH0773408A - Magnetic head and magnetic recording / reproducing apparatus equipped with the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain high reproduction output and good sliding characteristics in a magnetic head in which the main magnetic path is formed of single crystal ferrite. In a magnetic head having a main magnetic path formed of single crystal ferrite, the main magnetic path forming surface of the magnetic head is a (110) plane and <10 with respect to the normal direction of the sliding surface of the magnetic head.
The magnetic head is characterized in that the residual stress in the single crystal ferrite becomes tensile stress when the angle θ formed with 0> is approximately 90 °. [Effect] High reproduction output and good sliding characteristics can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head whose main magnetic path is made of single crystal ferrite.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, the recording wavelength has been shortened in order to achieve high density magnetic recording. Along with this, the recording medium is being made to have higher holding power. On the other hand, magnetic heads are now required to have high recording / reproducing capability capable of coping with high coercive recording media. Under such circumstances, various magnetic heads having a composite structure of a metal magnetic material and a ferrite single crystal material, which have high recording and reproducing ability, have been invented at present.

However, the magnetic head having a main magnetic path made of single crystal ferrite has the following problems. Generally, the magnetostriction constant of ferrite is on the order of 10 to ⁵ to 10 to ⁶ , and this value is one to two orders of magnitude larger than the values of metal magnetic core materials such as permalloy and sendust. Therefore, when stress is applied to the head, the magnetic characteristics of the ferrite portion are significantly deteriorated.

In an actual head, stress is always left in the ferrite portion due to the difference in thermal expansion coefficient between the ferrite and the metal magnetic film and between the ferrite and the bonded glass (in the case of a ferrite head, ferrite and the bonded glass). To do. Therefore, in order to prevent the deterioration of the head performance, it is essential to take measures against the magnetoelastic effect of ferrite.

In Japanese Patent Laid-Open No. 63-193310, the stress applied to the ferrite is formed by forming the ferromagnetic metal magnetic film to a depth dimension within the range from the tape sliding surface to the vicinity of the winding window at a depth length or more. And succeeded in improving the head performance.

[0006]

However, all of the above-mentioned inventions merely reduce the stress applied to ferrite, and are insufficient as a measure against the magnetoelastic effect. In order to completely implement this countermeasure, the stress applied to the ferrite should be adjusted so that the permeability of the ferrite becomes the highest, considering the direction and magnitude of the stress applied to the ferrite, and the relationship between the crystal orientation of the ferrite and the head performance. And it is necessary to set the crystal orientation of ferrite.

The present invention has been made in view of the above points, and an object thereof is to provide an excellent magnetic head realized by significantly reducing deterioration of magnetic characteristics of ferrite due to stress. Especially.

[0008]

[Means for Solving the Problems] As a result of detailed examination of the magnitude and direction of the residual stress in ferrite and the effect of the ferrite crystal orientation on the permeability of ferrite, the direction of the stress when stress is applied to ferrite It was clarified that the easy axis of magnetization of ferrite changes according to the size and the size. Therefore, in order to find the condition that gives the best reproduction characteristics of the head, consider the direction and magnitude of the stress applied to the ferrite, and then select the ferrite crystal orientation so that the ferrite permeability is maximized. There must be.

However, when considering practical use for a head, the crystallographic orientation of the selectable ferrite is limited. This is because the sliding characteristics of the head largely depend on the crystal orientation of ferrite. Therefore, in the present invention, the crystal orientation of ferrite (the crystal orientation shown in FIGS. 1 and 10) at which good sliding characteristics are obtained is first assumed, and the conditions for obtaining the best reproduction characteristics with this crystal orientation have been derived.

[0010]

In a magnetic head having a main magnetic path formed of single crystal ferrite, the main magnetic path forming surface of the magnetic head is the (110) plane and <10 with the normal to the sliding surface of the magnetic head.
Means such that when the angle formed with 0> is approximately 90 °, the residual stress in the single crystal ferrite is tensile stress, and the absolute value of the residual stress is σ · λ / K1 ≧ 1.0. In particular, the magnetic head characterized by taking the above steps is excellent in reproduction characteristics and sliding characteristics.

The present invention relates to a ferrite-metal composite magnetic head in which at least a part of a magnetic path is composed of a metal magnetic material, and the metal magnetic material is a ferrite containing Co group amorphous and Fe group crystalline. It is particularly effective in a metal magnetic head.

[0012]

EXAMPLES Examples of the present invention will be described in detail below.

<< First Embodiment >> FIG. 1 shows a first embodiment of the present invention.
3 is a schematic view of a magnetic head showing the embodiment of FIG. In this example, Mn-Zn single crystal ferrite was used as a core material, and V
This is an application example to the magnetic head 1 for TR. In FIG. 1, 2 is a first core half body (C-type core half body) made of Mn—Zn single crystal ferrite material, and 3 is a second core half body (I-type core half body) also made of Mn—Zn single crystal ferrite material. Body). The first and second core halves 2 and 3 are abutted on the front side and the rear side, and an operating gap 4 having a predetermined track width is formed on the front side with a gap regulating thin film (not shown) interposed. 5 is a fused glass, which integrally joins the first and second core halves. Reference numeral 6 denotes a winding window, which allows a coil (not shown) to be wound. Further, the sliding surface 7 and the main magnetic path forming surface 8 of the magnetic head 1 are (110) planes of the crystal orientation of Mn—Zn single crystal ferrite, and <100> and the normal direction to the sliding surface of the magnetic head. The angle θ formed by is approximately 90 °. At this time, the direction of the stress remaining in the ferrite was adjusted by the fused glass 5. Generally, the direction of stress (pulling stress, compressive stress) is determined by the magnitude relationship of the coefficient of thermal expansion with the members to be joined. However, it was experimentally clarified that the stress direction of the glass and the ferrite substrate cannot be explained only by the magnitude relation of the coefficient of thermal expansion. Therefore, regarding the glass used in this example, what kind of stress remains in the ferrite when bonded to the ferrite was confirmed by experiments. As a result, tensile stress remains in ferrite in glass A and compressive stress remains in ferrite in glass B, and the absolute values of the stress are about 50 to 70 in all cases.
It was revealed to be MPa.

FIG. 2 is a schematic view of the configuration of a magnetic recording / reproducing apparatus equipped with the magnetic head 1 according to the present invention. After mounting the tape cassette, the magnetic tape 23 is pulled out by a known tape loading mechanism to form a tape running system as shown in FIG. 2. The magnetic tape 23 is the pinch roller 1.
5 is supported by the capstan 16 and the capstan 16, and the capstan 16 is rotated to drive and drive in the direction of the arrow. Then, the traveling magnetic tape 23 and the rotating magnetic head 1 mounted on the upper cylinder 12 slide relative to each other to record and reproduce the video signal.

A method of manufacturing the magnetic head 1 shown in FIG. 1 will be described with reference to FIGS. 3 to 8 using a ferrite head as an example.

FIG. 3 shows a Mn-Zn single crystal ferrite block 31. As shown in the figure, the flat surface side having a large area is the (100) plane and each side surface is the (110) plane. . The composition of the single crystal block is Fe ₂ O ₃ : 5.
3 mol%, ZnO: 15 mol%, MnO: 33 mol%,
The crystal magnetic anisotropy constant is −500 erg / CC, the magnetostriction constants λ ₁₀₀ and λ ₁₁₁ are λ ₁₀₀ : −7 × 10 −6,
λ ₁₁₁ : 2 × 10 −6.

First, a pair of ferrite blocks 31 is prepared. As shown in FIG. 4, the winding groove 32 for the winding window 6 and the track groove 33 are formed in one of the base material blocks 31 by using a high precision dicer or the like, and the first core half body 2 is formed. The first base material block 31A is prepared. Further, as shown in FIG. 5, the track groove 33 is formed in the other base material block 31.
Is also formed using a high precision dicer or the like to form the second base material block 31B for the second core half body 3.

The above-mentioned fused glass 5 is adhered to the abutting surface of the above-mentioned first member block 31A,
Fused glass 5 in the winding groove 32 and the track groove 33 described above.
Is embedded. After that, the surface of the fused glass 5 and, if necessary, the first member block 31A is polished and removed so that a predetermined track width can be obtained, and the surface of the first member block 31A is selectively exposed. At the same time, the fused glass 5 in the winding groove 32 is removed. Then, on the abutting surface of the first member block 31A, S having a predetermined film thickness is formed.
A gap regulating thin film 34 of iO ₂ is deposited and formed. FIG. 6 shows the state after the end of this process (FIG. 6).
Then, the gap regulating thin film 34 on the fused glass 5 is omitted).

The above-mentioned fused glass 5 is also adhered to the abutting surface side of the second base material block 31B, and the fused glass 5 is embedded in the track groove 33. After that, the fused glass 5 is formed so that a predetermined track width is obtained.
And the surface of the 2nd base material block 31B is grind | polished and removed as needed, and the surface of the 2nd base material block 31B is selectively exposed. Then, on the abutting surface of the second base material block 31B, a gap regulating thin film 34 of SiO _{2 having} a predetermined film thickness is deposited and formed. FIG. 7 shows the state after the end of this process. (In FIG. 7, the gap regulating thin film 34 on the fused glass 5 is omitted).

Next, the first base metal block 31A of FIG. 6 and FIG.
The second base material block 31B is accurately aligned and abutted with the abutting surfaces. Then, the first and second base material blocks 31A and 31B are heat-bonded to the fused glass 5 and the gap regulating thin film 34 to form the first and second base material blocks 31A and 31B as shown in FIG. Create an integrated composite matrix block. This composite base material block is cut along a virtual line 35 in FIG. 8 with a high precision dicer or the like,
Then, the head 1 shown in FIG. 1 is obtained by subjecting the sliding surface to curved surface processing and mirror surface processing.

In this example, two types of heads were produced by using the above-mentioned glass A and glass B as the fused glass. FIG. 9 shows reproduction outputs measured by mounting the two types of magnetic heads on the magnetic recording / reproducing apparatus shown in FIG. Reference numeral 41 is a reproduction output of a magnetic head produced by using glass A as a fusion glass, and 42 is a reproduction output of a magnetic head produced by using glass B as a fusion glass. The tape used was a demagnetized oxide tape, and the relative speed of the magnetic head was 5.8 m / s. From the figure, it can be seen that the magnetic head using the glass A has a higher output of about 1.5 dB than the magnetic head using the glass B. That is, the angle θ formed by the sliding direction of the magnetic head and <100> is approximately 90.
In the case of °, the reproduction output becomes high when the tensile stress remains in the ferrite.

<< Second Embodiment >> FIG. 10 is a schematic view of a magnetic head according to a second embodiment of the present invention. This embodiment is an example of application to a VTR head adopting a ferrite-metal composite type structure. The ferrite single crystal used was the same Mn-Zn ferrite single crystal as that used in the first embodiment, and amorphous CoTaZr was used as the metal magnetic material.

Similar to the first embodiment, the angle θ formed by the direction normal to the sliding surface of the magnetic head and the ferrite crystal orientation <100> is about 90 °. The same glass as in the first example was used as the fusion glass.

In FIG. 10, 52 is the first core half (C
Shaped core half), 53 is the second core half (I type core half)
The first core half body 52 is mainly composed of a core base 54A made of Mn-Zn ferrite material and a metal magnetic film 55 made of amorphous CoTaZr. Also,
The second core half body 53 is also mainly composed of a core substrate 54B made of an Mn—Zn ferrite material and a metal magnetic film 55 made of amorphous CoTaZr. The core bases 54A and 54B are the first and second cores in the first embodiment.
It corresponds almost to the core halves 2 and 3. The first and second core halves 52, 53 are abutted on the front side and the rear side, and an operating gap 56 having a predetermined track width is formed on the front side with a gap regulating thin film (not shown) interposed. Reference numeral 57 is a fused glass, which integrally joins the first and second core halves 52 and 53. 58 is a winding window,
A coil (not shown) is wound. Also, M
The crystal orientation plane of the n-Zn single crystal ferrite is the (110) plane on the sliding surface 59 of the magnetic head 1 and the main magnetic path forming surface 60.

Next, a method of manufacturing the magnetic head shown in FIG. 10 will be described with reference to FIGS. FIG. 11 shows Mn
The base material block 61 of -Zn single crystal ferrite is shown. The crystal plane orientation of the base material block 61 is, as shown in FIG.
0) plane. The composition of the base material block 61 of this Mn-Zn single crystal ferrite is Fe in the present embodiment.
₂ O ₃ : 53 mol%, ZnO: 15 mol%, MnO: 33 mo
The crystal magnetic anisotropy constant is -500e.
rg / CC, magnetostriction constants λ ₁₀₀ and λ ₁₁₁ are respectively λ ₁₀₀ : -7
× 10 -6, λ ₁₁₁ : 2 × 10 -6 (base material block 6
1 is the same as the base material block 31 in FIG. 3).

A pair of the base material blocks 61 as described above is prepared, and the track grooves 62 are formed in the pair of base material blocks 61 by using a high precision dicer or the like as shown in FIG. Then, the metal magnetic film 55 made of amorphous CoTaZr is formed and formed in a predetermined thickness on the entire abutting surfaces of the two base material blocks 61, 61 forming a pair. At this time, a diffusion prevention film 64 is formed with a predetermined thickness between the Mn—Zn single crystal ferrite (base material block 61) and the metal magnetic film 55, if necessary. FIG. 13 shows a state in which the metal magnetic film 55 is formed on one of the base material blocks 61, but the same is true for the other base material block 61.

Then, the fused glass 5 is formed on the pair of base material blocks 61, 61 on which the metal magnetic film 55 is formed.
7 is deposited, and the fused glass 57 is embedded in the track grooves 52 of the pair of base material blocks 61, 61. After that, in the one base material block 61, the winding groove 63 is formed.
Is formed by using a high precision dicer or the like, and the first core half 52
A base material block 61 ′ to be (C core half body) is obtained. After that, in one of the base material blocks 61, as shown in FIG. 14, the surfaces of the fused glass 57 and the metal magnetic film 55 are polished and removed so that the predetermined track width is obtained, and the metal magnetic film 55 is selected. Exposed. Further, in another block 61 ′, as shown in FIG. 15, the fused glass 57 and the metal magnetic film 55 are selectively polished as necessary,
The metal magnetic film 55 is exposed by being removed. Thereafter, a gap-regulating thin film of SiO ₂ having a predetermined film thickness is formed and formed on the abutting surface side of each of the base material blocks 61 and 61 ′ shown in FIGS. 14 and 15.

Next, the base material block 61 of FIG. 14 and FIG.
The base material blocks 61 ′ of the above are accurately butted, and both blocks 6 are made by the fused glass 57 and the gap regulating thin film.
16 and 61 'are heat-bonded to each other to form a composite block in which both blocks 61 and 61' are integrated as shown in FIG. This composite base material block is cut along a phantom line 65 in FIG. 16 using a high-precision dicer or the like, and then the sliding surface is subjected to curved surface processing and mirror surface processing, whereby the composite base material block shown in FIG.
The magnetic head 51 as shown in 0 is obtained.

In this example, two types of heads were produced by using the above-mentioned glass A and glass B as the fused glass. FIG. 17 shows reproduction outputs measured by mounting the two types of magnetic heads on the magnetic recording / reproducing apparatus shown in FIG. In addition,
The tape used was a demagnetized oxide tape, and the relative speed of the magnetic head was 5.8 m / s. From the figure, glass A
It can be seen that the magnetic head using the above-mentioned magnetic head has a higher output of about 2.5 dB than the magnetic head using the glass B. That is,
Angle θ formed by the direction normal to the sliding surface of the magnetic head and <100>
Is about 90 °, the reproduction output increases when tensile stress remains in the ferrite.

[0030]

As described above, in the magnetic head having the main magnetic path formed of single crystal ferrite as described above, the main magnetic path forming surface of the magnetic head is the (110) plane and the direction normal to the sliding surface of the magnetic head. The magnetic head is characterized in that the angle formed with <100> is approximately 90 °, and that the residual stress in the single crystal ferrite becomes tensile stress. The magnetic head is particularly excellent in reproducing characteristics and sliding characteristics. It becomes a thing.

The present invention also relates to a ferrite-metal composite magnetic head in which at least a part of a magnetic path is composed of a metal magnetic material, and the metal magnetic material is a ferrite containing Co-based amorphous material and Fe-based crystalline material. -Especially effective in a metal magnetic head.

[Brief description of drawings]

FIG. 1 is a schematic external perspective view of a magnetic head according to a first embodiment of the invention.

2 is a perspective view of a main part of a tape running system of a VTR equipped with the magnetic head of FIG.

FIG. 3 is an explanatory diagram of a manufacturing process of the magnetic head according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of the manufacturing process of the magnetic head according to the first embodiment of the invention.

FIG. 5 is an explanatory diagram of a manufacturing process of the magnetic head according to the first embodiment of the invention.

FIG. 6 is an explanatory diagram of the manufacturing process of the magnetic head according to the first embodiment of the invention.

FIG. 7 is an explanatory diagram of a manufacturing process of the magnetic head according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram of a manufacturing process of the magnetic head according to the first embodiment of the present invention.

FIG. 9 is a diagram showing reproduction output of the magnetic head of the first embodiment of the present invention.

FIG. 10 is a schematic external perspective view of a magnetic head according to a second embodiment of the invention.

FIG. 11 is an explanatory diagram of the manufacturing process of the magnetic head according to the second embodiment of the invention.

FIG. 12 is an explanatory diagram of a manufacturing process of the magnetic head according to the second embodiment of the invention.

FIG. 13 is an explanatory diagram of the manufacturing process of the magnetic head according to the second embodiment of the invention.

FIG. 14 is a diagram illustrating the manufacturing process of the magnetic head according to the second embodiment of the invention.

FIG. 15 is a diagram illustrating the manufacturing process of the magnetic head according to the second embodiment of the invention.

FIG. 16 is an explanatory diagram of a manufacturing process of the magnetic head according to the second embodiment of the invention.

FIG. 17 is a diagram showing the reproduction output of the magnetic head of the second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic head, 2 ... 1st core half body which consists of Mn-Zn single crystal ferrite, 3 ... 2nd core half body which consists of Mn-Zn single crystal ferrite, 4 ... Working gap, 5 ... Fused glass, 6 ... Winding window, 7 ... Sliding surface, 8 ... Main magnetic path forming surface, 11 ... Rotating cylinder device, 12 ... Upper (rotating side) cylinder of rotating cylinder device, 13 ... Lower (fixed side) cylinder of rotating cylinder device, 14 ... Impedance roller, 15 ... Pinch roller, 16 ... Capstan, 17 ... Back tension post, 18 ... Supply reel, 19 ... Winding reel, 20 ... Voice erasing head, 21 ... Voice / control head, 22 ... Previous Width erasing head, 23 ... Magnetic tape, 51 ... Magnetic head, 52 ... First core half body, 53 ... Second core half body, 54A ... Co consisting of Mn-Zn single crystal ferrite Half body, 54B ... Core half body made of Mn-Zn single crystal ferrite, 55 ... Metal magnetic film, 56 ... Working gap, 57 ... Fused glass, 58 ... Winding window, 59 ... Sliding surface, 60 ... Main magnet Road formation surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Miura 1410 Inada, Katsuta City, Ibaraki Prefecture Hitachi Ltd. AV Equipment Division

Claims (5)

[Claims] 1. A magnetic head having a main magnetic path formed of single crystal ferrite, wherein a main magnetic path forming surface of the magnetic head is a (110) plane and a direction normal to a sliding surface of the magnetic head is <
A magnetic head characterized in that the stress remaining in the single crystal ferrite becomes tensile stress when the angle θ formed by 100> is approximately 90 °. 2. The magnetic head according to claim 1, wherein the residual stress in the single crystal ferrite is | σ · λ / K1 | ≧ 1.0. Here, σ: stress applied to ferrite λ: magnetostriction constant of ferrite (<100> direction) K1: crystal magnetic anisotropy constant of ferrite. 3. The thermal expansion coefficient of glass according to claim 1, wherein at least a part of the magnetic path is made of a magnetic metal material, the thermal expansion coefficient of glass is <the thermal expansion coefficient of ferrite and the thermal expansion coefficient of glass < A magnetic head selected so as to have a coefficient of thermal expansion of a metal magnetic film. 4. The metal magnetic material is a Co-based amorphous alloy film,
At least one of Fe or Co-based microcrystalline precipitation type alloy film
The magnetic head according to claim 1, wherein the magnetic head comprises: 5. A magnetic recording / reproducing apparatus equipped with the magnetic head according to claim 1.