JPS59194406A - High permeability magnetic material - Google Patents

Abstract

PURPOSE:To obtain magnetic material which has little temperature dependence and high permeability at the practical temperature range by doping the magnetic material containing Fe2O3, MnO and ZnO with CoO. CONSTITUTION:When the content of Fe2O3 is 53-54mol%, the composition of MnO and ZnO is selected in such a manner that the point at which K1 (the primary crystal magnetic unisotropy constant) +K2 (the secondary crystal magnetic unisotropy constant)/9=0 is to be, for instance -30 deg.C-30 deg.C. These raw materials are doped with 0.5-2.0mol of CoO and mixed so that the absolute values of K1 and K2 at the room temperature may be reduced and the point at which K1+K2/9=0 may be below zero. With this constitution, the magnetic material which has very little temperature dependence and the high permeability at the practical temperature range can be obtained and, if this material is introduced to make a magnetic head, that head can have very little variation of the permeability and the stable high output during the operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high magnetic permeability magnetic disc used in a head for recording and reproducing video signals.

Conventional Structure and Problems Conventionally, Mn--Zn single-crystal ferrite has been mainly used as a material for recording and reproducing heads for video signals. This is a characteristic generally required for magnetic heads, that is, a large magnetic permeability μ.

The saturation magnetic flux density Bs is small, the coercive force Hc is small, the Curie temperature Tc is high, and in addition, it has to withstand precision machining, has excellent wear resistance, and has low sliding noise when made into a head. This is due to the fact that the Mn-Zn single-crystal ferrite (RI) satisfies the characteristics of the Mn-Zn single-crystal ferrite in that the area is outside the usage band. It is strongly influenced by the remaining amount and temperature of each of the components of ferric oxide Fe2O3, zinc oxide ZnO, and manganese oxide MnO.If Is is 1 saturation magnetization for the crystal magnetic anisotropy constant, then μ'' From the relationship of s/IKI, the magnetic permeability 71 is inversely proportional to the magnetocrystalline anisotropy constant, and since K has a temperature dependence, μ also has a large temperature dependence.K-=Q In the vicinity of the composition where μ
shows the maximum, but the KyO point may be near room temperature or near low temperature depending on the composition of the material.

However, in the past, the set of materials 51 was selected so that the point =Q, where the magnetic permeability was determined, was achieved near room temperature. In general, the first-order magnetocrystalline anisotropy constant e K+
*If the second-order magnetocrystalline anisotropy constant is 2, then the magnetocrystalline anisotropy constant is defined as 1 + δ = 2. here,
δ is a constant related to the structure and orientation of the crystal. In the case of a cubic crystal structure, theoretically when the rotational 4iB mechanism is dominant for magnetic permeability, δ-1/9 and [~, K, +2/9 It is known that the magnetic permeability is maximized when =O. Also + + K2
/9 > o, easy magnetization direction < 100 >, K1+
The easy magnetization direction will be <111> at 2/9 (O). Therefore, if the point 2/920 at K, -1- is realized near room temperature, the magnetic permeability of the magnetic head will be the same as that of the tape. Due to temperature changes due to sliding, the direction of magnetization is easily changed from 100 to the entire surface,
<111>The entire surface is present (-, resulting in an extremely unstable value,
As a result, there is a considerable difference in output between immediately after use and after a certain amount of time.

Purpose of the Invention The present invention solves the following conventional problems. The purpose is to provide a high permeability magnetic material as a raw material.

Structure of the Invention In order to achieve all of these objects, the present invention provides K1-1-2/
When the point 9-0 becomes, for example, -30'C to 30'0, the MnO, ZnO, Fe2C)5 rTr composition is drilled and the additive is added to the cable trunk. Therefore, at room temperature, the value of x2 (-1 or 1-
) The temperature dependence of the magnetic permeability of the magnetic head in the practical temperature range by setting the point at which K2/9-0 is below 0°C, and the temperature dependence of the magnetic permeability of the magnetic head in the practical temperature range. It is.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 (d MnO: 29 mo1%, ZnO: 17 mo
mo1%.

1 in a composition with Fe2O3 of s 4 mo1%. In the figure, 1 (d K+
, 2 is the measurement result of fdK2, and abani, +2
/9 = o. By changing the composition a
The point can be moved to the left or right, but in this composition it is located at about -16°C.If about 1% of Coo as an additive is added to this composition, that is, MnO is 28.6% by mo1. , ZnO is 16.5
mo1%, Co.

When the temperature dependence of K, K2 is measured with a composition of 1 mo1% of Fe2O3 and 64 mo1% of Fe2O3, the results are shown in Figure 2.

In this set l, the point where + is 2/9-○ is about -
By adding a small amount of Tsukushi CoO, it is possible to move K, + to 2/9=O.
2/7)
As a result, the magnetic permeability (5kUl+) 9Before adding CoO/7) can be reduced from 620 to 1 because the absolute value can be reduced.
It can be made as thick as 740. Even if the amount of Coo added was changed by 0.5 mol% to 2.0 mol, it was possible to similarly increase the magnetic permeability in the practical temperature range. However, when it becomes -120!+101 coefficient or higher, the magnetic permeability shows a tendency to decrease [~.Therefore, the appropriate amount of Coo to be added is 0.6 mo1% to 2.□ mo1%0
As a second example, the point where 1+ becomes 2/9; O is 13.
Fe2O3 in 0'C~3Q'C is 53~ssmo
1%, ZnO 14-24 mo1%, 'MnO 2
A small amount of Goof is added to the composition of 1-33m01% (Fe2
O3 is 63-55 mo1%, Coo is 0.5-2.0
mo1%, the rest being MnO and znO), K, -)-K2/9=0 as in the first embodiment.
By making the point below O'C, we were able to confirm that the absolute value of 2 at room temperature can be made small. However, if Fe2O3 is below 53 mol, the amount of Coo added must be 2. There was a tendency for the magnetic permeability to decrease due to the large amount of Fe2O3.Also, as Fe2O3 is 55 mol, the absolute value of 1 and 2 at room temperature is large, so 000 is 0.6~2゜Omo1%. Although some degree of magnetic permeability was observed even when added, it did not reach a size that was strong enough to withstand use.Therefore, F+, 703 was 63-55m01%, and C00 was 0.6-2. .○mo1%
, the residue is MnO and ZnO (n composition is high permeability JAf1
: I think it is the most suitable material.

Detailed description of the invention
By setting the point where 2/9 = O to Kj+ to be less than O°0, and by increasing the absolute value of 2 to (9,
To obtain a high permeability magnetic material with extremely low temperature dependence and high permeability in a practical temperature range.
A magnetic head is manufactured using the material of the present invention (in the case of...
It is possible to create a magnetic head that produces a stable output with little change in magnetic permeability during use, so it can be used for long-time recording and playback VTRs and KNG VTs that can be used under harsh conditions.
It is used as an R head and has great industrial value.

[Brief explanation of drawings]

Is Figure 1 an additive? Figure 2 shows the measurement results of the temperature dependence of +K2 in the case of no addition of Coof. . Name of agent: Cali 111 Toshio Nakao and 1 other person
Name Procedural Amendment Document January 1980 // Mouth Patent Application No. 68709 of 1982 2 Name of the Invention High Permeability Magnetic Material 3 Person Making the Amendment 211 A.1 Relationship Patent Applicant Address Osaka Prefecture Kadoma City Oaza Kadoma 1006 address name
(582) Matsushita Electric Industrial Co., Ltd. Representative '1go
Toshihiko Yamashita 4th agent 〒57
1 Address: Matsushita Electric Industrial Co., Ltd., 1006 Kadoma, Kadoma City, Osaka Prefecture, 14. 6. Contents of amendment (1) “-16°C” on page 4, line 19 of the specification was changed to “
-18℃" (2) 1, page 5, line 11. " is corrected to "dekipuko."

Claims (2)

[Claims] (1) Contains at least ferric oxide Fe2O3, manganese oxide MnO, zinc oxide ZnOf, and further contains cobalt oxide C
A high permeability magnetic material characterized by the addition of 0.5 to 2.0 mo1%. (2) The content of ferric oxide Fe2O3 is 53-5smo
1%. A high magnetic permeability magnetic separator according to claim 1, which is characterized in that it is 1%.