JPH0358307A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve output while making best use of the advantages possessed by a magnetic head of a metal-in-gap type by regulating the compsn. and crystal bearing of ferrite in the magnetic head, the magnetic cores of which are constituted of ferrite and magnetic metallic thin films. CONSTITUTION:The magnetic head of the metal-in-gap type consisting of the ferrite core parts 1, 2 and the magnetic metallic thin films 3, 4 with a magnetic gap (g) as a boundary is constituted. Since the compsn. and crystal bearings of the ferrite largely affect the characteristics, the compsn. consisting of 51.5 to 54.5mol% Fe2O3, 16.0 to 20.0mol% ZnO and the balance MnO is adopted. As to the crystal bearing thereof, the crystal is so cut out that the Miller index of the sliding surface of a magnetic recording medium is (110) and the Miller index of the plane parallel with the magnetic gap (g) plane is (100). The output is improved while the advantages possessed by the magnetic head of the metal- in-gap type are best used if the magnetic head is formed in such a manner.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a magnetic head that performs recording and reproduction on and from a magnetic recording medium, and particularly relates to a magnetic head in which the magnetic core is made of ferrite and metal magnetic thin film. This invention relates to a so-called metal-in-gap magnetic head.

[Summary of the invention]

The present invention aims to improve output in a magnetic head whose magnetic core is composed of ferrite and a metal magnetic thin film by defining the composition and crystal orientation of the ferrite.

(Prior technology) Oxide magnetic materials are generally used as the core material of the 1i magnetic head, and ferrite is the most widely used among them, but ferrite alone lacks saturation magnetic flux density, and Since it is difficult to cope with recording and short wavelength recording, a so-called metal-in-ganop type magnetic head has been developed in which a metal magnetic thin film is combined.

This metal-in-gap type magnetic head has at least one half of the magnetic core made up of a ferrite core part and a metal magnetic thin film laminated on the ferrite core part facing the magnetic gap, The aim is to utilize the high saturation magnetic flux density of metal magnetic thin films to cope with high-density recording and short-wavelength recording.

(Problem to be Solved by the Invention) By the way, the recording wavelength of magnetic heads for electronic still cameras and magnetic heads for video tape recorders is becoming shorter and shorter. Studies are being conducted on materials such as ferrite and metal magnetic thin films, but when trying to use conventional metal-in-gap magnetic heads as recording/playback heads for these electronic still cameras and video tape recorders, the output is low. In particular, the lack of chroma output has become a problem, and improvements are desired.

Furthermore, in conventional metal-in-gap magnetic heads, so-called "waviness", in which the frequency characteristics of the reproduced signal periodically fluctuate, is often observed. This is because the interface between the ferrite and the metal magnetic thin film acts as a pseudo gap, which interferes with the magnetic flux passing through the original magnetic gap to generate a pseudo signal.

As described above, although the metal-in-gap type magnetic head has many advantages, there are also many problems to be solved, and in particular, it is desired to improve the output and solve the problem of pseudo-gap as soon as possible.

The present invention has been proposed in view of the conventional situation, and is a magnetic head that takes advantage of the advantages of the metal-in-gap type magnetic head and has even higher output, particularly excellent chroma output characteristics. The purpose is to provide

Another object of the present invention is to provide a magnetic head with less waviness due to the pseudo cassob.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the magnetic disk of the present invention has a magnetic core made of ferrite and a metal magnetic thin film, and the ferrite's Mi precept is Fet 0
351.5-54.5 mol%, ZnO16.0-2
0.0 mol%, the balance being MnO, and is characterized in that the sliding surface of the magnetic recording medium has a surface index of (110) and the surface parallel to the magnetic gap surface has a surface index of (100). .

[Effect]

The magnetic core is made of ferrite and a metal magnetic thin film.
In an in-gap magnetic head, the composition and crystal orientation of the ferrite greatly affect the characteristics. In particular, the composition is 51.5 to 54.5 mol% Few○3, 16.0 to 20.0 mol% ZnO, and the balance is MnO.
As for the crystal orientation, the plane index of the sliding surface of the magnetic recording medium is (110). The plane index of the plane parallel to the magnetic gap plane is (
100), the output can be improved.

〔Example〕

Hereinafter, specific embodiments to which the present invention is applied will be described with reference to the drawings.

First, FIG. 1 shows an example of a metal-in-gap type magnetic head in which a metal magnetic thin film is arranged parallel to a magnetic gap. FIG. 2 is an enlarged view of this magnetic head viewed from the sliding surface of the magnetic recording medium.

This magnetic head is made by joining magnetic core halves (+) and (II) separately on the left and right sides with a magnetic gap g as a boundary, and joining them together by glass fusing.

Each magnetic core half-hole (1), (It) is mostly Mn.
- Ferrite core part (1) made of Zn ferrite,
(2), and the abutting surface (la) of these ferrite core parts (1) and (2),
Along (2a) metal magnetic thin It! (3) , (
4) is prohibited. Metal magnetic thin 1]l (3),
As the material for (4), any soft magnetic metal (alloy) material that is used in this type of magnetism can be used, examples include Fe-Affi-Si alloy (so-called Sendust alloy). Fe-Ga-Si alloy, Fe-Al
-Ge alloy, Fe-Ga-Ge alloy, Fe-Si-
Ge based alloy, Fe-Si-Co based alloy. Fe-CoSi
Examples include crystalline soft magnetic alloy materials such as -Aji alloys, and amorphous soft magnetic alloy materials such as so-called metal-metalloid amorphous alloys and metal-metal amorphous alloys.

The magnetic core halves (1) and ([[) are joined so that the metal magnetic thin films (3) and (4) face each other via a gap spacer made of fused glass, Sin, film, etc. , therefore these metals are magnetic! Ill (
3) A magnetic gap g is established between the opposing surfaces of (3) and (4).

In addition, in the wooden example, ferrite core parts (1) and (2)
The positions of both ends of the magnetic gap g between the metal magnetic thin films (3) and (4) are shaved off into a substantially circular arc shape, thereby increasing the track width Tw of the magnetic gap g between the metal magnetic thin films (3) and (4). is regulated. In addition, the grooves (5) and (6) are filled with a non-magnetic material such as glass in order to ensure contact characteristics with the magnetic recording medium and prevent uneven wear due to sliding contact of the magnetic recording medium. Sections (7) and (8).

Furthermore, the ferrite core portion (1) of one magnetic core half (1) is provided with a groove (5) for regulating the track width.
A winding groove (9) is provided in a direction perpendicular to the magnetic core half-hole (H, (II)) so as to form a winding hole for winding the coil when the magnetic core half-holes (H, (II)) are butted against each other. .

In the magnetic head having the above-described structure, the ferrite core portions (1) and (2) are assembled in the F
e. 0.51.5 to 54.5 mol%, Z n 0
16.0 to 20.0 mol% 1 balance MnO (that is, the area surrounded by diagonal lines in FIG. 3).

This is done in consideration of the characteristics required of the magnetic head. For example, if FezO2 is too high or low outside the above range, the magnetocrystalline anisotropy will increase, which is undesirable, and the magnetic permeability characteristics will deteriorate. decreases, and the playback output also decreases. On the other hand, as for ZnO, if the amount of ZnO is too small outside the above range, the magnetostriction constant becomes large and it becomes difficult to use it as a magnetic head material. In other words, although the saturation magnetic flux density is high, noise increases and characteristics vary widely. On the other hand, if the amount of ZnO exceeds the above range, the saturation magnetic flux density will decrease and the recording characteristics will deteriorate.

In addition, in the above range, FezO3 and Zn
The proportion of O is important, and the remainder may contain some additives in addition to MnO. On the other hand, the crystal orientation of each of the ferrite core parts (1) and (2) is as shown in FIG. 4 with only the ferrite core part (1) taken out.
The surface index of the magnetic recording medium sliding surface (lb), <2b> is (1
10), and the plane parallel to the magnetic gap g (in this example, the abutting plane (la) of each ferrite core part (1) and (2))
, (2a) corresponds to this. ] has a surface index of (10
0).

In addition, the side surfaces (
lc) The surface index of (2c) is (110). However, among the above-mentioned surface indexes, the magnetic recording medium sliding surface (1b)
(2b) represents the surface index in the state before cylindrical polishing.

The present inventors conducted various experiments regarding the difference in characteristics depending on the composition and crystal orientation of ferrite, and the experimental results will be described in detail below.

Sj Rainbow L In this experiment, we mainly investigated the difference in output due to Fuyuraite's second command.

&[l of the ferrite adopted in this experiment or A in Fig. 3
Point B, Point C, and Point C.

String A (point A): FezOx 53.5 mol%
Z n O 19.0 mol% M n O 27.5 mol% Group B (point B): Fezos 53.6
Mol% Z n O 17.5 Mol% M n O 2B. 9 mol% Group C (point C): Fe. ○s 55.5 mol%Z
n O 21.8 mol% M n O 22.8 mol% The produced magnetic head has a structure similar to that shown in FIG. ), (2b) whose plane index is (100) A plane parallel to the magnetic gap g [Abutting plane (1a) (2a)
) was cut out so that the surface index was (110). Hereinafter, such a crystal orientation will be referred to as type B for convenience.

For each sample head, a 7 MHz signal output and 1. The signal output of the 2 MHz chroma was investigated. The results are shown in Table 1.

Table 1 Looking at this Table 1, although there is no big difference in the output at 7 MHz, the chroma output at 1.2 MHz falls within the composition range specified by the present invention (encircled by diagonal lines in Figure 3). An improvement of about 3 dB was observed in the samples (Sample 1 and Sample 2) using ferrite that fell into the ferrite region.

Of the ferrite compositions mentioned above, magnetic heads were made using ferrites with compositions A and M1-B, which had good properties, and changes in properties due to differences in crystal orientation were investigated. The crystal orientation adopted was B type, which is the same as in Experiment 1, and the plane index of the magnetic recording medium sliding surface (lb) and (2b) was (211
). The plane index of the plane parallel to the magnetic gap g is (111).
The crystal orientation is such that the plane index of the side surface is (110) (hereinafter referred to as J type for convenience). In conventional metal-in-gap magnetic heads, most of the ferrite cores are of this J type.

These sample heads were also examined for their 7 MHz signal output' and 1.2 MHz chroma signal output.

The results are shown in Table 2.

Table 2 As is clear from Table 2, the output is improved when the ferrite crystal orientation is B type. Furthermore, composition A
For the sample, we investigated the waviness caused by the pseudo gap in the B-type and J-type cases. As a result, in sample 4, which is type B, the waviness in the frequency characteristics of the reproduced output was 0. 3 dB, whereas in sample 5, which is a J type, the waviness was 2. 5 d
A significant difference from B was observed.

That is, it has been demonstrated that specifying the crystal orientation of ferrite as type B is advantageous from the viewpoint of pseudogap.

Although the present invention has been described above based on specific examples and experimental results, the present invention is not limited to these examples. That is, although the above-mentioned embodiment applies the present invention to a magnetic head in which a metal magnetic thin film is arranged parallel to a magnetic gap, the present invention is not limited to this and can be applied to metal-in-gump type magnetic heads in general. For example, it can be applied to a magnetic head where a metal R thin film is arranged diagonally to a magnetic gap, or a magnetic head where a metal N thin film is arranged in an X shape with a magnetic gap in between. Applicable.

[Effects of the Invention] As is clear from the above explanation, in the magnetic head of the present invention, the ferrite composition and crystal orientation are optimized, so the output can be improved and the metal-in-. It is possible to provide a magnetic head that has the advantages of the Gasob type 6B magnetic head and also has excellent chroma output characteristics.

In addition, the undulation due to the pseudo gap can be significantly reduced, which is very effective in putting the metal-in-gap type Lft air pressure into practical use.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a magnetic head to which the present invention is applied, and FIG. 2 is an enlarged plan view showing the sliding surface of the magnetic recording medium. FIG. 3 is a schematic perspective view of a ferrite core used in the magnetic head of the present invention, and FIG. 4 is a schematic perspective view of a ferrite core for explaining the crystal orientation of ferrite. Ferrite core part/metal magnetic thin film

Claims (1)

[Claims] The magnetic core is composed of ferrite and a metal magnetic thin film, and the ferrite has a composition of Fe_2O_351.5-54.
．． 5 mol%, ZnO 16.0 to 20.0 mol%, balance M
nO, and the surface index of the sliding surface of the magnetic recording medium is (11
0), the plane index of the plane parallel to the magnetic gap plane is (100)
A magnetic head characterized by: