JPH0562114A - Magnetic head - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce sliding noise. In a magnetic head in which a magnetic gap abutting surface of a magnetic ferrite core 1 is composed of a metal magnetic thin film 2 having a high saturation magnetic flux density, the magnetic ferrite core 1 is composed of a rear core portion 1B composed of polycrystalline magnetic ferrite and at least magnetic recording. It is composed of a joined body with the front core portion 1F made of single-crystal magnetic ferrite that constitutes the contact surface 3 with the medium.

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 so-called metal-in-gap type magnetic head, in which the magnetic gap abutting surface of magnetic ferrite is a metal magnetic thin film having a high saturation magnetic flux density B _S. ..

[0002]

2. Description of the Related Art In order to improve the recording density, a magnetic recording medium having a high coercive force is used, and a magnetic head having a high saturation magnetic flux density B _S is required correspondingly.

As a magnetic head based on this requirement, there is a so-called metal-in-gap type magnetic head.

The metal-in-gap type magnetic head is
As shown in the schematic perspective view of FIG.
Pair of core halves 11A and 11B made of crystalline ferrite
Having magnetic ferrite cores 1 made of
Saturation magnetic flux density B on the mating end face _SWith high sendust and ammo
Metal magnetic thin film 2 such as rufus magnetic material is sputtered
It is formed by being attached.

As described above, the magnetic head constructed by the magnetic ferrite core 1 made of single crystal ferrite has low modulation noise and the contact surface with the magnetic recording medium is made of single crystal ferrite having high density. There is an advantage that the contact surface can be formed as a surface having excellent specularity that is unlikely to cause defects.

In this case, since most of the magnetic path is occupied by the single crystal ferrite, the characteristics of the single crystal ferrite are largely reflected in the recording / reproducing characteristics of the head.

Therefore, in this case, in order to improve the recording / reproducing characteristics, the composition of the single crystal ferrite is selected,
Select the desired characteristics for the head core.

Specifically, for example, in Mn-Zn ferrite, by increasing the composition of Fe ₂ O ₃ , the anisotropy constant K is brought close to K = 0, and the magnetic permeability μ
And the saturation magnetic flux density B _S is increased,
In this case, the inconvenience that the sliding noise is greatly deviated from the region of the magnetostriction constants λ ₁₀₀ and λ ₁₁₁ = 0 and the sliding noise is increased, the sliding noise is low by selecting the composition of the single crystal ferrite, and the recording / reproducing It is difficult to obtain a magnetic head with excellent characteristics.

On the other hand, when the polycrystalline ferrite is used as the magnetic ferrite core 1, the modulation noise becomes high, defects are likely to occur on the contact surface with the magnetic recording medium, and the magnetic permeability is particularly near the magnetic gap. However, there is a problem that the magnetic path direction cannot be increased sufficiently.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a magnetic head having a small sliding noise and excellent recording / reproducing characteristics in the metal-in-gap type magnet using the above-mentioned magnetic ferrite.

[0011]

As shown in an enlarged perspective view of an example of the present invention in FIG. 1, the abutting surface of a magnetic gap g of a magnetic ferrite core 1 is made of a metal magnetic thin film 2 having a high saturation magnetic flux density. In the magnetic head, the magnetic ferrite core 1 is a joined body of a rear core portion 1F made of polycrystalline magnetic ferrite and a front core portion 1B made of at least a single crystal magnetic ferrite constituting a contact surface 3 with a magnetic recording medium. It consists of.

In the above structure, the depth from the magnetic gap surface of the contact surface 3 of the front core portion 1F made of single crystal ferrite with the magnetic recording medium is L, L ≦ 100 μm.
And more preferably when the gap depth is D _P ,
D _P ≦ L ≦ 100 μm.

[0013]

According to the above-described structure of the present invention, the portion forming the magnetic path that crosses the magnetic gap g and the contact surface 3 with the magnetic recording medium are formed of single crystal ferrite, so that the composition is saturated. By selecting an advantageous composition in terms of magnetic density B _S, magnetic permeability μ, magnetic anisotropy, etc., a magnetic head having excellent recording / reproducing characteristics can be constructed, and the problem of loss of polycrystalline ferrite can be avoided. it can.

In the rear core portion 1B, in which the cross-sectional area of the magnetic path is large and the influence of B _S and μ is not so severe, polycrystalline ferrite having a small magnetostriction constant is used, so that sliding noise can be reduced. You can

Further, the thickness of the front core 1F made of single crystal ferrite, that is, the depth L from the tip of the gap g thereof.
When the relationship between this L and the sliding noise level is measured,
As shown in the results shown in FIG. 2, it can be seen that the sliding noise abruptly increases at 100 μm or more, but can be reduced at L ≦ 100 μm.

The depth L of the front core portion 1F
Is at least the magnetic gap gap depth D _{P in} consideration of the receding of the contact surface 3 with the magnetic recording medium due to wear due to sliding contact with the magnetic recording medium.

Thus, the sliding noise can be reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIG.

The magnetic ferrite core 1 is replaced with a core half 11A.
And 11B butts.

Each of the core halves 11A and 11B is formed by joining and joining a front core portion 1F made of single crystal ferrite and a rear core portion 1B made of polycrystalline ferrite.

On the surfaces of the core halves 11A and 11B facing each other, a Fe--Al--Si system having a high B _S ,
Fe-Ga-Si-Ru-based crystalline material, Fe-N, F
e-C, Fe-O based microcrystalline material, Co-Zr based, Co-
The metal magnetic thin film 2 is deposited by sputtering of Nb-based amorphous material or a vapor deposition film.

Reference numeral 4 denotes a winding groove for winding a head winding formed on at least one of the core halves.

The front core portion 1F and the rear core portion 1B are made of Mn.
It may be composed of a single crystal or a polycrystalline Zn-based ferrite. The depth of the front core portion 1F is the gap depth D.
Select from _p to 100 μm.

Example 1 In the magnetic head shown in FIG.
Co ₈₃ Zr ₈ Pd _{4 of} B _S = 12 kG on the mutually facing surfaces of the joined ferrite core halves 11A and 11B, each of which consists of a front core portion 1F and a rear core portion 1B made of Zn-based single crystal ferrite and polycrystalline ferrite. The metal magnetic thin films 2 made of an amorphous alloy film of Mo ₅ (the subscript number is atomic%) were sputtered to a film thickness of 6 μm. The joining of the core halves 11A and 11B, that is, the joining between the metal magnetic thin films 2 is performed by a low temperature metal joining method in which an Au layer is formed on a Cr underlayer by heating and pressing at 250 ° C.
After that, a track width of 86 is obtained by performing a magnetic field treatment at 350 ° C.
The head has a size of μm and a gap length of 0.3 μm. Regarding the crystallographic direction of the front core portion 1F, the contact surface 3 with the magnetic recording medium was the (100) plane, and the tape transfer direction orthogonal to the magnetic gap surface was the <100> axis. Comparative Example 1 The structure of FIG. 3 was the same as that of Example 1 except that the magnetic ferrite core 1 was a single crystal ferrite over the entire area.

Using the magnetic heads of Example 1 and Comparative Example 1, the sliding noise level was measured on the same metal tape. In this measurement, the noise level of system noise was measured with a spectrum analyzer without running the tape, and then the demagnetized magnetic tape was run for 10 minutes in an environment of a temperature of 40 ° C. and a relative humidity of 10%, and sliding at that time. The noise level was also measured by a spectrum analyzer. The measurement results are shown in Table 1 below.

[0026]

[Table 1]

The sliding noise in this case is processed as an average value at 2 to 12 MHz using a noise meter.

As is apparent from Table 1, according to the present invention, sliding noise is improved.

In the illustrated example, the magnetic gap g has a so-called parallel structure in which the magnetic gap g extends along the track width direction of the contact surface 3 with the magnetic recording medium. The present invention can be applied to a metal-in-gap type magnetic head having an inclined structure, and various modified structures can be adopted without being limited to the above example.

[0030]

As described above, according to the present invention, in a metal-in-gap type magnetic head for a high coercive force magnetic recording medium, modulation noise and recording / reproducing characteristics can be improved and sliding noise can be prevented. Since it can be reduced, it brings a great advantage in practical use.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a magnetic head according to the present invention.

FIG. 2 is a measurement curve diagram showing the relationship between the depth of the single crystal front core portion and sliding noise.

FIG. 3 is a perspective view of a conventional magnetic head.

[Explanation of symbols]

 1 magnetic ferrite 1B rear core part 1F front core part 11A core half body 11B core half body 2 metal magnetic thin film 3 contact surface with magnetic recording medium 4 winding groove g magnetic gap

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kaoru Aoki 6-5-6 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Magne Products Co., Ltd. (72) Yukari Utsumi 6-chome, Kita-Shinagawa, Shinagawa-ku, Tokyo No. 5 and 6 in Sony Magne Products Co., Ltd.

Claims (3)

[Claims] 1. A magnetic head in which a magnetic gap abutting surface of a magnetic ferrite core is made of a metal magnetic thin film having a high saturation magnetic flux density, wherein the magnetic ferrite core is a rear core portion made of polycrystalline magnetic ferrite, and at least a magnetic recording medium. A magnetic head comprising a joined body with a front core portion made of single-crystal magnetic ferrite constituting a contact surface with the magnetic head. 2. The magnetic head according to claim 1, wherein
The depth L from the magnetic gap surface of the front core portion, which is made of single crystal ferrite, facing the magnetic recording medium is L ≦ 10.
A magnetic head having a thickness of 0 μm. 3. The magnetic head according to claim 1, wherein:
When the depth from the magnetic gap surface of the front core portion made of single crystal ferrite with the magnetic recording medium is L and the gap depth is D _P , D _P ≦ L ≦ 100 μm head.