JPH0413206A - Magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a laminated magnetic head used for magnetic recording and reproducing. The perspective view of the magnetism shown in the publication, Figure 8, shows this magnetic l\\
FIG. 2 is an enlarged view of the Watt magnetic tape sliding surface viewed from above.

In the figure, (1) is a non-magnetic reinforcing material such as ceramic as a base material, (2) is reinforced glass, (3) is a wire window, and (4) is a reinforced glass.
) is a magnetic gap, (5) is a plurality of metal magnetic films, (6)
is an insulating film such as S + 02 that insulates between the metal magnetic films (5), (7) is a laminated magnetic film, and (1) to (7) constitute a magnetic head (8), and (9) is a laminated magnetic film. is the sliding movement of the magnetic tape. .

FIG. 9 shows a V T'F<
FIG. 2 is a diagram showing recording tracks of FIG. In the figure, (10)
is a magnetic tape, (at, (bl is a recording track).

In order to increase the recording density, recent VTRs perform guard band recording with no gaps between tracks. Actually, as shown in the figure, the magnetic head (8)
It has a track width wider than the track pitch d, and is configured to perform the aging of the portion fc) in the figure. This is because the track that is actually made has a bend due to the vibration of the rotating tram, and the track is...! Since the pitch fluctuates, there is a risk that a guard band will be formed if recording is performed using a magnetic track width that is the same as the theoretical track pitch.This is to prevent this, as it is possible to predict output deterioration during both recordings. .

[Problem that the invention attempts to solve]

When reproducing with a conventional magnetic head (8), the track width of the magnetic head (8) is wider than the track pitch d, so there is a problem that signals from adjacent tracks are also picked up, causing crosstalk. Ta. To solve this problem, there is a technique called azimuth recording, but the effect was not sufficient.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain a magnetic head that can reduce crosstalk from adjacent tracks.

[Means for Solving the Problems] A magnetic head according to the present invention is one in which the thickness of the laminated metal magnetic films is different in the track width direction, and the metal magnetic film in the portion where the magnetic gap is overwritten is It is characterized in that it is formed by laminating thin metal magnetic films, and the remaining portion is formed by a relatively thick metal magnetic film.

[Effect]

In the laminated magnetic film of the present invention, the reproduction ability of the laminated portion of the thin metal magnetic film is high, and the reproduction ability of the remaining portion is low, so the level of the signal reproduced from the adjacent track is lowered, reducing crosstalk. do.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, the laminated magnetic film (7) is composed of a thick metal magnetic film (50) and a laminated portion of thin metal magnetic @ (511 to (53)).

FIGS. 5 and 6 are characteristic diagrams showing the relationship between the film thickness and magnetic properties of a metal magnetic film. Among the magnetic properties, those related to recording and reproduction include permeability Fdi and saturation magnetization. Figure 5 is Toru M
This is a frequency characteristic diagram of the i-rate, where the characteristic curve (a) is the characteristic curve when the metal magnetic film is thick, and the characteristic curve (b) is the characteristic curve when the film is thin. 7. Magnetic permeability decreases at high frequencies due to eddy current loss peculiar to metals, so it is necessary to increase the magnetic permeability by making the film thinner and not allowing current to flow. This results in the characteristics shown in (b) in the figure. Furthermore, it is known that the saturation magnetization does not change unless the film thickness is extremely thin. The horizontal axis in FIG. 6 is on the order of several tens of dimensional planes, and only about several hundred squares, and since the track width is on the order of microns, there is no problem at all.

Now, during reproduction, among the characteristics of the head core material, the magnetic permeability, which determines the high frequency characteristics, has the greatest influence and is highly dependent on the film thickness. During recording, in addition to magnetic permeability, saturation magnetization, which determines how strong a magnetic field can be, has a large effect.

From the following points of view, the magnetic head (8) of this embodiment
Although the recording capacity is almost the same, during reproduction, the magnetic permeability of the thinner metal magnetic films (51) to (53) is higher than that of the thicker metal magnetic film (50). It is efficient and produces an effect as if the track width had become smaller.

As a result, as shown in Fig. 10, the magnetic t\...nod (8) moves across the original amphibious track (al) and the adjacent track (bl), resulting in M'l;
, the magnetic permeability of the portion of the magnetic head (8) above the track fbl is low, so the reproduction efficiency is low, and the track (al
Since the magnetic permeability of the track (a) is high and the reproduction efficiency is high, the signal of the original reproduction track (a) is selectively reproduced.

Furthermore, during recording, although the efficiency is largely dependent on the saturation magnetization level as described above, the efficiency is affected by magnetic permeability. 11th
As shown in the figure, the thinner part (b-1), which is determined later, will age more strongly than the thicker part. Tsuku (a-2)
It is expected that the crosstalk due to the unerased 4a Si will be reduced. Of course, the recorded track width is wider than the track pitch and is still a guardless recording.

Note that the laminated metal magnetic films (501, +511 to (53
According to the vacuum thin film forming technology, changing the film thickness of ) can be easily achieved by simply changing the forming time, so there is no cost penalty.

In the above embodiment, the thickness of the laminated metal magnetic film was changed in two stages, but it may also be configured to gradually become thinner as shown in FIG.

In addition, as shown in Figure 3, the film thickness at the center of the track is made thinner to increase playback efficiency, playback occurs at the center of the track to reduce crosstalk, and even if the track is curved, the signal will not be picked up. It is also possible to have an arbitrary configuration.

Furthermore, as shown in FIG. 4, a structure in which the laminated magnetic film (7) is inclined with respect to the tape running direction may be used, and the same effect can be obtained.

[Effects of the Invention] As described in F below, according to the present invention, high frequency signal permeability is changed in the head width direction by changing the thickness of the magnetic film of a magnetic head in which a magnetic gap is formed with a laminated magnetic film.
Since the recording and reproducing capabilities are made different, it is possible to obtain a magnetic head with less crosstalk due to adjacent tracks or overwriting.

[Brief explanation of drawings]

1 to 3 are partially enlarged front views of the magnetic tape sliding surface near the magnetic gap of different embodiments of the present invention, and FIG. 4 is a partially enlarged front view of the magnetic tape sliding surface of another embodiment of the invention. 5 is a characteristic diagram of changes in magnetic permeability depending on the film thickness of the metal magnetic film, FIG. 6 is a saturation magnetization characteristic diagram, FIG. 7 is a perspective view of a conventional multilayer magnetic head, and FIG. 8 is a partially enlarged front view of the magnetic tape sliding motion near the magnetic gap in this conventional example, FIG. 9 is a diagram showing the recording pattern by the conventional magnetic head, and FIGS. 10 and 11 are the implementation shown in FIG. 1. FIG. 6 is a diagram for explaining operations during reproduction and recording by the example magnetic head. (1)...Nonmagnetic reinforcing material, (4)...Magnetic gap, (50)-(53)...Metal magnetic film, (6)...
Insulating film, (7)... Laminated magnetic film, (8)... Magnetic head. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A magnetic head formed by forming a magnetic gap by abutting first and second core halves each having a plurality of layers of metal magnetic films laminated on a base material, and forming a magnetic gap by abutting the metal magnetic film laminated portions, which A magnetic head characterized in that a laminated metal magnetic film is formed by dividing it into a part where a thin metal magnetic film is laminated and a part where a thick metal magnetic film is laminated.