JPH0827901B2 - Magnetic head - Google Patents

Description

The present invention relates to a magnetic head for performing magnetic recording and reproduction at high density.

[Conventional technology]

As shown in FIG. 4, a composite of ferrite and a metal magnetic thin film, which is formed by forming metal magnetic thin films 3 and 3 on the gap abutting faces 2.2 of a pair of conventional ferrite single crystal cores 1.1, respectively. Magnetic heads are known. In this magnetic head, the main magnetic path forming surface 4 of the ferrite single crystal core 1 is usually configured to be the (110) surface or its vicinity.

Further, the above-mentioned ferrite single crystal core 1.1 is disclosed in
As in Japanese Patent Laid-Open No. 56-163518, in the plane 8 perpendicular to the magnetic gap 7, the tape sliding including the <100> direction B and the magnetic gap 7 is carried out similarly to the magnetic head formed of only the ferrite single crystal core. Angle β with plane 9 perpendicular to plane 5
Is set to 5-40 ° or 85-120 °. As an example of such a magnetic head, the angle β is about 35.
°, tape sliding surface 5 is (211) surface or its vicinity, gap abutting surface 2 and core side surface 6 parallel to it are (11
1) When the surface curvatures are arranged in the vicinity of the cores, if the ferrite single crystal cores 1.1 in the magnetic head are etched using hydrochloric acid etc., one apex will be formed on each of the core side surfaces 6 and 6. It is possible to observe an equilateral triangular etch pit 10 in which only 10a is located on the side opposite to the tape sliding surface 5.

[Problems to be Solved by the Invention]

Like the above magnetic head, the angle β is 5 to 40 ° or
If the angle is set to 85 to 120 °, it is disclosed in Japanese Patent Laid-Open No. 163518/1981.
As described in Japanese Patent Publication No. JP-A-2003-264, in a magnetic head composed only of a ferrite single crystal core, the recording / reproducing characteristics are good.

In particular, as described in Japanese Patent Publication No. 61-6443, if the <100> direction B is set so that only one apex 10a of the etch pit 10 is located on the opposite side of the tape sliding surface 5, the ferrite simple The recording / reproducing characteristics of the magnetic head composed only of the crystal core are excellent. Therefore, in the above composite magnetic head, the ferrite single crystal core 1
Since 1 plays an important role in operation, the magnetic flux at the time of recording / reproducing will flow in the ferrite single crystal core 1.1.

By the way, in the above-mentioned composite magnetic head, the metal magnetic thin films 3 and 3 are arranged in the vicinity of the magnetic gap 7 which comes into contact with the magnetic tape at the time of recording / reproducing. Since the magnetic flux passes through the single crystal core 1.1, the magnetic flux flows in the thickness direction C of the metal magnetic thin film 3.3 during recording and reproduction. However, since the magnetic permeability of the metal magnetic thin films 3, 3 in the thickness direction C is extremely small, the magnetic resistance in the portion of the metal magnetic thin films 3, 3 for recording / reproducing on / from the magnetic tape becomes large, and the recording / reproducing efficiency decreases. Was invited.

[Means for solving the problem]

In order to solve the above-mentioned problems, a magnetic head according to claim 1 in the scope of claims of the present specification has a pair of ferrite single crystal cores and a gap abutting surface near each ferrite single crystal core. In the magnetic head having the formed metal magnetic thin film, the (110) plane of the ferrite single crystal core is made substantially parallel to the main magnetic path forming plane, and the <100> direction existing in the (110) plane The magnetic tape includes a magnetic gap, and the angle formed by the plane perpendicular to the tape sliding surface is in the range of 0 to 5 ° or 120 to 180 °.

The magnetic head according to claim 2 is the magnetic head according to claim 1, wherein the magnetic head exists within the (110) plane.
It is characterized in that the angle formed by the <00> direction and the plane including the magnetic gap and perpendicular to the tape sliding surface is 145 °.

[Work]

According to the above construction, the magnetic recording characteristics of the ferrite single crystal core portion in the magnetic head composed of the ferrite single crystal core and the metal magnetic thin film are the same as those described in JP-A-56163518. It is far inferior to a magnetic head consisting of only. Therefore, in the magnetic head comprising the ferrite single crystal core and the metal magnetic thin film of the present invention, the magnetic flux during recording / reproduction becomes difficult to flow through the ferrite single crystal core body, and therefore, mainly in the in-plane direction of the metal magnetic thin film, that is, , It will flow in the direction perpendicular to the thickness direction. In that case, since the magnetic permeability in the in-plane direction of the metal magnetic thin film is considerably higher than that in the thickness direction, excellent recording / reproducing characteristics can be obtained as compared with the conventional composite magnetic head.

Note that the main magnetic path formation surface of the ferrite single crystal core should be (11
By setting the direction other than the (0) plane, the magnetic recording / reproducing characteristics in the ferrite single crystal core portion can be inferior to the conventional one, but in that case, it is most likely to be the main magnetic path forming surface. A plane other than the (110) plane, which has a high magnetic permeability, is used. As described above, in the composite magnetic head using a surface other than the (110) plane of the ferrite single crystal core as the main magnetic path forming surface, the magnetic resistance of the entire magnetic head increases, and the magnetic recording / reproducing characteristics deteriorate.

On the other hand, in the composite magnetic head of the present invention, the (110) plane of the ferrite single crystal core, which is a high magnetic permeability surface, is used as the main magnetic path formation surface, and the magnetic resistance of the entire magnetic head is kept small while the ferrite single crystal core is kept small. The magnetic flux can be suppressed from flowing into the crystal core during magnetic recording and reproduction, and the metal magnetic thin film can be effectively operated.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the magnetic head comprises a pair of ferrite single crystal cores 11 and 11, and one ferrite single crystal core 11 is provided with an internal winding groove 11a. A metal magnetic thin film 13 having a high magnetic permeability and a high saturation magnetic flux density is formed on the gap abutting surfaces 12, 12 of each ferrite single crystal core 11, and the metal magnetic thin films 13, 13 sandwich the magnetic gap 14 and the glass 15, etc. Are bonded to form a magnetic head.

Each ferrite single crystal core 11 has a main magnetic path forming surface 16 (11
0) It is set to be almost parallel to the surface 20. Further, each ferrite single crystal core 11 has a plane 21 in which the <100> direction A present in the (110) plane 20 includes the magnetic gap 14 and is perpendicular to the tape sliding surface 17 as shown by the dotted line.
The angle θ between and is 0-5 ° or 40-85 ° or
It is set to be in the range of 120 to 180 °.

In the above range, the angle θ at which the effect of the present invention is particularly remarkable is about 145 °, the tape sliding surface 17 is the (211) surface or its vicinity, the gap abutting surface 12 and the core side surface parallel thereto.
When the ferrite single crystal core 11 in the magnetic head is etched with hydrochloric acid or the like when 18 is arranged to be the (111) plane or its vicinity, as shown in FIG. Only one vertex 22a is tape sliding surface 1
The etch pit 22 located on the 7 side can be observed.

According to the above structure, as described above, the recording characteristics of each ferrite single crystal core 11 are significantly lower than those of the conventional magnetic head, so that the magnetic flux during recording and reproduction is reduced.
・ It becomes difficult to flow inside 11, and mainly metal magnetic thin film 13 ・ 13
The gas flows in the inside along the in-plane direction D having high magnetic permeability. As a result, the metal magnetic thin film 13
Since the magnetic resistance at 13 becomes small, good recording and reproducing characteristics can be obtained.

FIG. 2 shows the results of measuring the reproduction output for each of the present invention and the conventional composite magnetic head having the same gap length, the same shape, and the same inductance, as a relative value.
However, the angle θ in the two ferrite single-crystal cores 11 and 11 in the composite magnetic head of the present invention whose reproduction output is shown by the solid line I are both about 145 °, and the conventional composite magnetic head whose reproduction output is shown by the dotted line II. The angles corresponding to the above-mentioned angle θ in the two ferrite single crystal cores in are both about 35 °.
The coercive force of the magnetic tape used for recording / reproducing with the present invention and the conventional composite magnetic head was set to 900 oersted, and the relative speed between the magnetic tape and the magnetic head was set to 5.8 m / sec.

As is clear from FIG. 2, the magnetic head of the present invention has a range of 2 to 2 in the entire frequency band as compared with the conventional magnetic head.
5dB playback output is improved.

Further, FIG. 3 shows the reproduction output (indicated by the solid line I) when the angles θ in the two ferrite single crystal cores 11 and 11 are both about 145 ° in the composite magnetic head of the present invention, respectively. Angle θ between two ferrite single crystal cores 11 and 11
Output when both are set to about 35 ° (displayed by dotted line II)
And the reproduction output when the angle θ in the ferrite single crystal core 11 on the side where the internal winding groove 11a is provided is approximately 145 ° and the angle θ in the other ferrite single crystal core 11 is approximately 35 ° ( (Indicated by the one-dot chain line III) and the angle θ in the ferrite single crystal core 11 on the side where the internal winding groove 11a is provided is about 35 °, and the angle θ in the other ferrite single crystal core 11 is about 145 °. The reproduction output (indicated by the one-dot chain line IV) in the case of is shown as a relative value.

As is apparent from FIG. 3, when the angles θ in the two ferrite single crystal cores 11 and 11 of the composite magnetic head are both set to about 145 °, as shown by the solid line I, in other cases II to
The playback output was higher in all frequency bands compared to IV.

〔The invention's effect〕

As described above, the magnetic head according to the present invention is a magnetic head having a pair of ferrite single crystal cores and a metal magnetic thin film formed in the vicinity of a gap abutting surface of each ferrite single crystal core. The (110) plane of is substantially parallel to the main magnetic path forming surface, and the <100> direction existing in the (110) plane and a plane including the magnetic gap and perpendicular to the tape sliding surface. The angle formed by is in the range of 0 to 5 ° or 120 to 180 °.

As a result, the magnetic recording / reproducing characteristics of the ferrite single crystal core are significantly inferior to the conventional ones.
The magnetic flux at the time of recording / reproducing becomes hard to flow in the ferrite single crystal core, and mainly flows in the in-plane direction of the metal magnetic thin film, that is, in the direction perpendicular to the thickness direction. In that case, since the magnetic permeability in the in-plane direction of the metal magnetic thin film is considerably higher than that in the thickness direction, excellent recording / reproducing characteristics can be obtained as compared with the conventional magnetic head.

If the <100> direction existing in the (110) plane and the plane including the magnetic gap and perpendicular to the tape sliding surface form an angle of 145 °, the present invention The effect can be most remarkably exhibited.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a schematic perspective view of a magnetic head, and FIG. 2 is a relative reproduction output of the magnetic head of the present invention and a conventional magnetic head. FIG. 3 is a graph showing the values of the magnetic head of the present invention (11
0) A graph showing the relative values of the respective reproduction outputs when the angle formed by the <100> direction in the plane and the plane containing the magnetic gap is variously changed. FIG. 4 is a schematic view of a conventional magnetic head. It is a perspective view. 11 is a ferrite single crystal core, 12 is a gap abutting surface, 13 is a metal magnetic thin film, 20 is a (110) surface, 21 is a flat surface, A
Is in the <100> direction.

Claims (2)

[Claims] 1. A magnetic head having a pair of ferrite single crystal cores and a metal magnetic thin film formed in the vicinity of a gap abutting surface of each ferrite single crystal core, wherein the (110) plane of the ferrite single crystal core is the main magnetic field. It is almost parallel to the road formation surface and exists in the (110) plane <1
00> direction and the plane that includes the magnetic gap and is perpendicular to the tape sliding surface are 0 to 5 ° or 120 to 180
A magnetic head characterized in that it is configured to be in a range of °. 2. An angle between the <100> direction existing in the (110) plane and a plane including the magnetic gap and perpendicular to the tape sliding surface is 145 °. The magnetic head according to claim 1, wherein: