JPS6037699Y2 - magnetic head - Google Patents

Description

[Detailed Description of the Invention] This invention aims to obtain a magnetic head with high electromagnetic conversion efficiency.

The electromagnetic conversion efficiency of a magnetic head is affected by the degree of convergence of magnetic flux near the magnetic gap, and if the convergence is sharp, the electromagnetic conversion efficiency can be increased.

By the way, as a constituent material of a magnetic head, Mn is generally used.
-Zn-based single crystal ferrite is often used, and its magnetic anisotropy constant is K # -10" to +lQ"erg/cc, which is very small compared to cobalt, ferrite, etc. When manufacturing a magnetic head, no consideration was given to the direction of easy magnetization.

However, in magnetic heads that are extremely thin and have a small cross-sectional area of the magnetic path, the saturation magnetic flux density of ferrite is smaller than that of alloy materials, so if the direction of easy magnetization is not taken into consideration, the magnetic saturation This causes a decrease in the degree of magnetic flux convergence, leading to a decrease in conversion efficiency.

In particular, as recording density increases, the gap width becomes narrower.
Moreover, as the coercive force of the tape increases, its influence becomes greater.

Therefore, the inventor conducted experiments to determine which direction should be chosen as the direction of easy magnetization.

Figures 1 to 4 show Mn-z as a magnetic material, respectively.
4-crystal ferrite is used, and the direction of easy magnetization is <110
5 and 6 show their characteristics.

FIG. 1 is a perspective view of a magnetic head according to an embodiment of the present invention, and the magnetic head A shown here has cores 4a and 4a'.
The easy magnetization directions 5a and 5a' of the main surface of the magnetic head A (
In a plane parallel to the upper and lower surfaces (in a plane perpendicular to the magnetic gap 1), a plane including the magnetic gap 1 and perpendicular to the tape sliding contact surface 2 (joint surface of cores 4a, 4a', hereinafter referred to as The angles θ and θ' with respect to the gap surface (referred to as the gap plane) are each 35 degrees.

Here, 3 is a coil.

In the above embodiments, θ and θ′ were explained as an example of 35 degrees, but the angles are not necessarily limited to this, and may be set to 55 degrees, 75 degrees, etc., for example.

(Refer to magnetic head E and magnetic head F in FIGS. 5 and 6 described later) Similarly, the magnetic head B shown in FIG.
The magnetic head C shown in FIG.
, 5C' are both oriented at 145 degrees, and the magnetic head D shown in FIG. 4 has the easy magnetization directions 5d and 5d' of both cores 4d and 4d' both oriented at 90 degrees. It is.

FIG. 5 shows the reproduction output of each of the magnetic heads A to F.

As is clear from this figure, the magnetic head A according to the present invention shown in FIG. 1 and the magnetic head A of the present invention shown in FIG.
For example, magnetic head E and magnetic head F with θ' set to 55 degrees and 75 degrees have IMHzv 3MHz and 5MHz.
At all frequencies of z, the highest output is obtained, followed by magnetic head B shown in Fig. 2, magnetic head C shown in Fig. 3, and magnetic head D shown in Fig. 4 has the lowest output. There is.

From this, it can be seen that it is preferable to orient the easy magnetization direction so that the angle measured toward the magnetic gap direction is an acute angle with respect to the gap surface.

In other words, it is preferable to combine the directions of easy magnetization of the left and right cores so that they each face the magnetic gap on the tape sliding surface within a plane perpendicular to the magnetic gap.

From this point of view, magnetic head B is the same as magnetic head A with respect to the core 4b, and is the same as magnetic head C with respect to the core 4b'. It can be seen that the following output is obtained.

FIG. 6 shows the optimum recording voltage for each of the magnetic heads A to F.

The optimal recording voltage here means that when recording on a magnetic medium, if the voltage applied to the magnetic head is gradually increased, the reproduction output will also increase, but it will reach a peak at a certain point, and if the voltage is applied beyond that point, the output will increase. Playback output decreases.

At this time, the recording voltage at this peak is called the optimum recording voltage.

In other words, a head that requires a low optimum recording voltage can be said to be an efficient head.

As is clear from this figure, the magnetic head E has the smallest input, that is, the highest recording sensitivity.

However, in this case, the magnetic head C has lower sensitivity than the magnetic head D.

The recording sensitivity is (Im/, v/l,)-', and the reproduction sensitivity is ceo, /jL) (Im is the saturation recording current, eo
is the reproduction output voltage and L is the inductance of the head), and when these values at 5MH2 are calculated and tabulated, the following is obtained.

However, if the impedances are equal, the recording sensitivity (1
m/,,/L)-1 is (V/-/L)-” (V
is the saturation recording voltage), the relative ratio does not change, so (
V/7L)-” was substituted.

As is clear from this table, for example, there is a 1.2 dB difference in recording sensitivity between heads A and C, and a 3.8 dB difference in reproduction sensitivity between heads A and D.

As is clear from the above experimental results, the easy magnetization direction <110> of the left and right magnetic cores of the anisotropic magnetic material constituting the magnetic gap is within the plane perpendicular to the magnetic gap.
The angle between the easy magnetization direction 110〉 and a plane that includes the magnetic gap and is perpendicular to the tape sliding contact surface is configured to form an acute angle from this plane toward the tape sliding contact surface. The magnetic head has better recording sensitivity and reproduction sensitivity than conventional magnetic heads.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic head of the present invention, and FIGS. 2 to 4 are perspective views of magnetic heads of the present invention which are different from the magnetic head of FIG. 1 in the direction of easy magnetization. FIG. 5 is a graph showing their output characteristics, and FIG. 6 is a graph showing their optimum recording voltage characteristics. 1... Magnetic gap, 2... Tape sliding contact surface, 4, 4 a/... Core, 5a, 5a'.
...Easy direction of magnetization.

Claims (1)

[Scope of utility model registration request] In a plane in which the easy magnetization direction <110> of the anisotropic magnetic material constituting the magnetic gap is perpendicular to the magnetic gap, the easy magnetization direction <110> is a plane that includes the magnetic gap and is perpendicular to the tape sliding surface. The magnetic head is configured so that the angle formed by the surface is an acute angle from this surface toward the tape sliding surface.