JPH0118561B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a magnetic head using an oxide magnetic material as a core material, and more particularly to an improvement of a magnetic head using an MnZn ferrite material as a core material. Various materials are used as magnetic materials for magnetic heads, ranging from metals to ferrite. Among these, ferrite materials have a particularly large electric resistivity ρ, and therefore a large magnetic permeability μ up to high frequencies.
It is widely put into practical use today because it has the advantages of extremely high wear resistance, resulting in little wear due to magnetic tape sliding, and because it is a chemically stable substance. In particular, the frequency used is 4.
In the magnetic heads of computers, VTRs, etc., which have a frequency of ~5MHz, ferrite materials are almost always used. However, magnetic heads using ferrite materials have the disadvantage of producing large noise when sliding on a magnetic tape. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional magnetic head and to provide a magnetic head with low magnetic head sliding noise. In order to achieve the above object, the present invention is characterized in that MnZn ferrite added with In ₂ O ₃ is used as a core material. In the present invention, the composition of the MnZn ferrite matrix is MnO 21 to 36 mol%, ZnO 13 to 25 mol%,
and 50 to 56 mol% of Fe ₂ O ₃ .
In addition, in the present invention, the amount of In ₂ O ₃ added is 0.01 to
It is desirable that it be 5.0wt%, and the reason is that
If In ₂ O ₃ is not added to the matrix, no improvement in head performance can be expected, and if the amount added exceeds 5.0 wt%, both μ and noise characteristics will deteriorate significantly.
This is because it cannot exhibit its performance as a magnetic material. Hereinafter, the present invention will be explained in detail based on Examples. Example 1 MnO29 mol%, ZnO 18 mol%, Fe ₂ O ₃ 53 mol%
In ₂ O ₃ of 0, 0.01, 0.5, 1.0,
They were added in proportions of 3.0, 5.0 and 7.5 wt%, mixed in a ball mill, dried, calcined at 900°C for 3 hours, and ground again in a ball mill. A portion of the crushed powder is further added with a binder, granulated, and shaped.
It was fired at 1380°C for 6 hours to obtain a polycrystalline ferrite material. Further, a part of the above-mentioned pulverized powder was placed in a platinum crucible and melted, and then the crucible was lowered and gradually cooled from the tip of the crucible to grow single crystal ferrite. Magnetic heads were made using the polycrystalline and single-crystalline ferrite materials obtained in this way, and their head characteristics were measured. The results are shown in Tables 1 and 2. Table 1 shows the results of measuring the output and noise of a VTR magnetic head made of single-crystal ferrite with a track width of 60 μm at 4 MHz.

[Table] Table 2 shows the measurement results of the head characteristics of an audio magnetic head made using polycrystalline ferrite. The head track width was 600 μm, the tape speed was 47 mm/sec, and the measurement frequency was 333 Hz.

【table】

[Table] From Tables 1 and 2, In ₂ O ₃ is 0.01 to 5.0wt.
It is clear that when a MnZn ferrite material containing 1.5% of the MnZn ferrite material is used as a core material, the noise is greatly improved in both VTR magnetic heads and audio magnetic heads. Example 2 Composition A (MnO25 mol%, ZnO25 mol%,
Fe ₂ O ₃ 50 mol%), composition B (MnO36 mol%, ZnO14
mol%, Fe ₂ O ₃ 50 mol%), composition C (MnO 21 mol%, ZnO 23 mol%, Fe ₂ O ₃ 56 mol%), composition D
(MnO3 1 mol%, ZnO 13 mol%, Fe ₂ O ₃ 56 mol%), and compositions E and F each made by adding 1 wt% of In ₂ O ₃ to the matrix consisting of each of the above compositions A, B, C, and D. , G, and H were prepared in the same manner as in Example 1 to obtain single-crystal ferrite and polycrystalline ferrite. Next, these ferrite materials are
We fabricated it into a magnetic head for VTR and measured the head characteristics. The results are shown in Table 3. The track width is 60μm, and the head output and noise are
Measured at 4MHz.

[Table] As is clear from the results shown in Table 3,
The magnetic head of the present invention using an MnZn ferrite material doped with In ₂ O ₃ as a core material is particularly effective in reducing noise. As detailed above, the magnetic head according to the present invention has a composition of 1 to 36 mol% MnO2, ZnO13
MnZn consisting of ~25 mol%, _{Fe2O3 50-56} mol%
A magnetic head using an oxide magnetic material containing 0.01 to 5.0 wt% of In ₂ O ₃ in ferrite as a core material can greatly improve its noise characteristics, so it has great industrial effects. .

Claims (1)

[Claims] 1 MnO21-36 mol%, ZnO13-25 mol%,
MnZn ferrite consisting of 50-56 mol% Fe ₂ O ₃ ,
A magnetic head with low noise characteristics characterized by using an oxide magnetic material containing 0.01 to 5.0 wt% of In ₂ O ₃ as a core material.