JP2529292B2 - Magnetic head - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a magnetic recording device such as a flexible magnetic disk device used as an external storage device in various electronic devices.

2. Description of the Related Art In recent years, magnetic recording apparatuses have been made smaller and have higher capacities. Therefore, recording media are required to have high coercive force, and magnetic heads are required to have high density recording characteristics. In addition, the gap length of the magnetic head is becoming shorter in order to reproduce a shorter wavelength.

By the way, when trying to record on a magnetic medium with a high coercive force using a magnetic head made of ferrite, which has been widely used in the past, magnetic flux saturation occurs in the operating gap portion, which causes a problem that sufficient recording cannot be performed. Was there. Therefore, a magnetic head using a Fe-Si-Al alloy, which is a highly saturated magnetic material, was developed as the core material. However, since this kind of alloy is very expensive, a magnetic head as described below has been developed. That is, the above-mentioned highly saturated magnetic material is formed on the operation gap contact surface of the magnetic core to prevent the saturation of the magnetic flux, which is called a MIG head (metal-in-gap head).
Next, three types of the MIG head will be described with reference to FIG. FIG. 3 (A) is a double-sided type in which a highly saturated magnetic thin film is formed on both of the gap contact surfaces, and FIG. 3 (B) is the surface on the trailing side when recording / reproducing on / from a magnetic recording medium. This is a single film type in which the above thin film is formed only on the top surface, and in contrast to the above (B), the thin film is formed only on the leading side surface, as shown in FIG. By the way, the types (A) and (C) described above deteriorate the reproduction output due to the deterioration of the magnetic characteristics of the magnetic thin film to be formed, especially the magnetic permeability μ, and also due to the pseudo gap generated at the boundary surface between the thin film and the core material. The noise output at the time of reproduction becomes a cause of lowering the resolution. On the other hand, according to the experiment, the type (B) type has become the mainstream in the MIG head because the noise is less generated. A cross section of the (B) type magnetic head is shown in FIG. In the figure, 1 is a first core made of ferrite, 2 is a second core facing the first core with an operating gap 3 in between, and a high saturation magnetic thin film 4 is provided on the first core 1. Are formed. In addition, 5 is an apex part for regulating the gap depth, and 6 is a glass filled in the apex part 5 and the operating gap 3.

Problems to be Solved by the Invention Even in the magnetic head configured as described above, if the gap depth becomes shallower as the magnetic head becomes smaller and the gap becomes narrower, as shown in FIG. There is a problem that magnetic saturation occurs in the apex portion on the side, the leakage magnetic flux increases in this portion, and high-density recording cannot be performed.

Means for Solving the Problems In the present invention, among the operation gap contact surfaces of the first and second cores, the operation gap contact surface of the first core is composed of only the first thin film. The operation gap contact surface of the second core is composed of the second core and the second thin film, and the second thin film is not exposed at the sliding surface with the magnetic recording medium. The apex part of the second core was composed of the second thin film, and the first core side was the trailing side during recording / reproduction on the recording medium.

The highly saturated magnetic thin film formed in the action apex portion and its vicinity prevents magnetic saturation from occurring in the apex portion at the time of recording, and since it is separated from the recording medium, it hardly functions at the time of reproduction.

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

FIG. 1 is a view of a magnetic head of one embodiment as seen from a sliding surface with a magnetic recording medium, and FIG. 2 is an enlarged sectional view.

In the figure, 11 is a first core made of ferrite,
Reference numeral 12 is a second core that faces the first core with an operating gap 13 in between. A highly saturated magnetic thin film 14 made of a Fe—Si—Al alloy is formed on the first core 11 by sputtering. There is. The range indicated by a is the operation gap abutment surface of the first core 11, and the range indicated by b, that is, the sliding surface side of the apex portion 15 to be described later with the magnetic medium is the operation of the second core. It is a mating surface with a gap.

A high saturation magnetic thin film 17 is also formed by sputtering on the apex portion 15 and the inclined portion 16 for controlling the gap depth of the magnetic head. In addition, 18
Is a glass filled in the apex portion 15 and the operating gap 13, and serves to bond the first and second cores and to secure the strength of this portion.

The magnetic head of the present embodiment configured as described above operates as follows. That is, at the time of recording, the apex section 15
Since the magnetic resistance in the apex portion is reduced by the action of the highly saturated magnetic thin film formed on the inclined portion 16, even if the recording current is increased for recording on a recording medium having a high coercive force,
Good recording is performed without magnetic saturation occurring in this portion. In addition, the high saturation magnetic thin film 17 and the second core 12
Since the boundary portion between and is separated from the sliding surface 19 with respect to the recording medium, the adverse effect of picking up the magnetic flux as a pseudo gap does not occur.

EFFECTS OF THE INVENTION As described above, according to the present invention, among the operation gap contact surfaces of the first and second cores, the operation gap contact surface of the first core is composed of only the first thin film. The operation gap contact surface of the second core is composed of the second core and the second thin film, and the second thin film is not exposed on the sliding surface with respect to the magnetic recording medium. Since the apex part of the second core is composed of the second thin film and the first core side is the trailing side at the time of recording / reproducing to / from the recording medium, magnetic saturation occurs in the apex part at the time of recording. In addition, since the boundary portion with the core is separated from the sliding surface with the recording medium, there is no adverse effect such as picking up the magnetic flux as a pseudo gap, and the recording medium with high coercive force is not generated. Good recording and playback It is very effective in practice.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the magnetic head of the present invention, and FIG.
FIG. 3 is an enlarged sectional view of the magnetic head of the embodiment, FIG. 3 is a plan view of three types of MIG heads, FIG. 4 is an enlarged sectional view of a conventional magnetic head, and FIG. 5 is a magnetic medium of the magnetic head. It is a characteristic curve figure which shows the relationship between the position of a sliding surface, and the amount of the leakage magnetic flux at the time of recording. 11 …… first core, 12 …… second core, 13 …… operating gap, 14 …… high saturation magnetic thin film, 15 …… apex part, 16
…… Inclined part, 17 …… Highly saturated magnetic thin film, 18 …… Glass, 19
... Sliding surface with recording medium

Claims (2)

(57) [Claims] 1. A first core and a second core are joined together via an operating gap, and first and second cores made of a high saturation magnetic flux material are respectively provided to the first core and the second core. A magnetic head provided with a thin film, the first and second magnetic heads
Of the respective operating gap abutting surfaces of the cores, the operating gap abutting surface of the first core is composed only of the first thin film, and the operating gap abutting surface of the second core is the second thin film. The second thin film is composed of a core and a second thin film, and the second thin film is not exposed on the sliding surface with respect to the magnetic recording medium, and the apex part of the second core is the second thin film.
And a trailing side at the time of recording / reproducing on / from a recording medium. 2. The magnetic head according to claim 1, wherein a Fe-Si-Al alloy is used as the high saturation magnetic flux material.