JP3167308B2 - Magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for magnetic recording and reproduction, and more particularly to an image file, an auxiliary storage device for a computer, a VTR,
The present invention relates to a magnetic head that can be applied as a magnetic head for a magnetic recording device such as a tape recorder and a head for a local weak magnetic field sensor such as a magnetic flaw detection sensor and a magnetic latent image type document reading sensor.

[Conventional technology]

Conventionally, various magnetic recording devices such as computer auxiliary storage devices, VTRs, and tape recorders have been put into practical use, but in general, image files have a large amount of information.
There is a need for a system that enables high density recording and enormous transfer rates. Further, digitization is inevitable from the viewpoint of mixing and reliability with other files and preventing image deterioration due to repeated copying. Therefore, there is a need for a system configured with an appropriate image signal band compression technique.

In this case, the configuration of the magnetic head and the tape medium is a promising candidate as a large-scale and high-transfer-rate system, but the technical issues are the adoption of perpendicular magnetic recording that enables high-density and the miniaturization of the system. Therefore, development of a fixed high-efficiency head in place of a rotary head used in a VTR has been desired.

[Problems to be solved by the invention]

The problem in realizing perpendicular recording using a fixed type head is to increase efficiency, and there are attempts to achieve realization using an MR head using the magnetoresistive effect. However, there is a problem in reliability, etc., and it has not yet been put to practical use.

Therefore, a method of detecting a change in the high-frequency magnetic permeability at the main pole of the magnetic head has been proposed (Journa
l of the Magnetics Society of Japan Vol.13,
No.S1 (1989)).

However, this type of head has been aimed at improving the efficiency of the head alone, not utilizing the magnetic coupling between the head and the medium, but based on the narrowest track possible. It was not something.

The present invention has been made in view of the above circumstances, and can realize high-density track recording and high linear density recording, and can be easily multi-headed, and has a high transfer rate recording system for digital image files and the like. It is an object of the present invention to provide a magnetic head that can realize the above.

[Means and actions for solving the problem]

The present invention provides a magnetic head for recording / reproducing information on / from a magnetic recording medium, comprising: a main detecting magnetic pole arranged close to the magnetic recording medium; and a detecting coil provided around the main magnetic pole. And an exciting coil for exciting a high-frequency magnetic field, wherein once the magnetic recording medium is subjected to magnetization fluctuation by the high-frequency magnetic field of the exciting coil, the coupling with the magnetic recording medium is in a strong magnetization transition region. Using the fact that the main pole undergoes oscillation and the inductance changes, or that the main pole and the medium magnetic coupling change in the magnetization transition region, the change in the magnetization state of the magnetic recording medium due to the magnetization oscillation is The change in the inductance or the change in the main magnetic pole and the medium magnetic coupling is detected by the detection coil.

Further, in the magnetic head, the magnetic recording medium is a perpendicular magnetic recording medium having magnetization regions in mutually opposite vector directions, and a high-frequency magnetic field excited by an exciting coil is applied to the magnetic recording medium once through a main magnetic pole for detection. The method is characterized in that the magnetization in the guided perpendicular magnetic recording medium, particularly the magnetization transition region, is oscillated.

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a configuration example of a magnetic head of the present invention. In FIG. 1, reference numeral 1 denotes a main magnetic pole of a magnetic head, 2 denotes an exciting coil, 3 denotes an exciting power supply, 4 denotes a detecting coil, 5 denotes a detection amplifier system, 6 denotes a magnetic recording medium, and 7 denotes a transition area. Is shown.

The present invention focuses on a unique magnetization state near the medium magnetization transition of the magnetic recording medium 6 and completes the realization of a head system that uses this and the magnetic coupling of the head main pole 1 for reproduction. .

For example, the main magnetic pole 1 for detection of the head is located near the perpendicular magnetic recording medium 6 using an air-floating slider or the like and a support mechanism (or by directly sliding the head and the medium like a normal floppy disk). An excitation coil 2 and a detection coil 4 are provided near the main magnetic pole 1 in the head. Then, magnetization fluctuation is applied to the medium by the exciting coil 2, and a change in the internal magnetization state with respect to the exciting magnetic field is finally detected by the detection coil 4.

2 (a) and 2 (b) are diagrams for explaining the principle of signal detection by the magnetic head of the present invention. Hereinafter, the principle of detection will be described with reference to FIG.

In FIG. 2A, when a high-frequency magnetic field is applied to the main magnetic pole 1 by the exciting coil 2, the main magnetic pole 1 receiving the high-frequency magnetic field works not as a path of the magnetic flux but as a variable inductor. That is, in the vicinity of the magnetic transition region 7 where the coupling between the head and the medium 6 is strong, the main magnetic pole magnetization is fluctuated by the medium magnetization, and the inductance is increased in terms of a circuit. Therefore, detecting the rate of change of the inductance with the detection coil 4 is an example of the simplest realization method.

As another method, the method of head-medium magnetic coupling is changed. As shown in FIG. 2 (b), an exciting magnetic pole 1 'is provided separately from the main detecting magnetic pole 1, and an exciting magnetic field is provided. Is directly introduced into the magnetic recording medium 6 so that the magnetization transition region 7 of the magnetic recording medium 6 can be directly subjected to magnetization fluctuation. In this case, the main magnetic pole 1 does not function as a source of the high-frequency magnetic field but functions as a detection unit for detecting a signal associated with the head-medium magnetic coupling according to the medium magnetization state.

Next, FIGS. 3 (a) and 3 (b) correspond to FIGS.
(B) shows an equivalent circuit diagram corresponding to each,
FIG. 3A is an equivalent circuit when detecting the magnetization fluctuation of the main magnetic pole 1 from the rate of change of the inductance, and FIG.
Shows an equivalent circuit for detecting a signal accompanying the head-medium magnetic coupling.

In any case, the main magnetic pole 1 is desirably a material having a high effective magnetic permeability at a high frequency, and the magnetic recording medium 6 is preferably a material whose magnetization transition state changes rapidly. Specifically, as the main magnetic pole, an amorphous film such as Co-Zr-Nb or a laminated film thereof, a thin film of iron nitride or the like, or a laminated film thereof is effective. Also, in the medium,
In the vicinity of the magnetization transition point, Co
-A Cr alloy thin film or its laminated film is considered to be effective.

In terms of electric circuits, a configuration using an excitation magnetic field on the order of GHz is advantageous in terms of efficiency. One of the features of the present invention is that a simple structure that enables multi-track parallel processing can be realized relatively easily, but this part can be realized by a dedicated IC or a discrete external circuit. is there.

In the description of the principle of the present invention, a perpendicular magnetization medium is used as a magnetic recording medium. However, even if a longitudinal magnetization medium in which needle-like particles of iron oxide are applied is used, the basic effect and configuration remain the same. .

〔Example〕

 Next, specific examples of the present invention will be described.

FIG. 4 is a schematic configuration diagram of a magnetic head showing a specific embodiment of the present invention.

In FIG. 4, in this embodiment, the exciting coil 2 is a ferrite core 1 'for exciting to increase the magnetic field strength.
It is arranged close to. The main magnetic pole film 1 for magnetic coupling with the medium 6 is arranged close to the medium 6. The detection coil 4 is formed on the main magnetic pole thin film by using a thin film process or the like. In the configuration of this embodiment, one-sided access is advantageous, but in this case, multi-tracking is easy.

 Next, the actual operation will be described.

In FIG. 4, when a high frequency is supplied from the external excitation power supply 3, the high frequency magnetic field excited by the excitation coil 2 and the ferrite core 1 'is once guided to the medium 6 through the main magnetic pole 1 for detection, and the magnetization in the medium is fluctuated. Move. Then, the main magnetic pole-medium magnetic coupling changes due to the large swing in the medium magnetization transition region 7. Therefore, this change is detected by the detection coil 4 and the detection circuit amplifier 5.

Next, FIG. 5 is a schematic configuration diagram of a magnetic head showing another embodiment of the present invention, which aims to improve detection efficiency by accessing both sides. FIG. 5 shows an example of a multi-track configuration.

The detection unit assembly 10 includes a plurality of main magnetic pole films 1, a plurality of detection coils 4, and a detection amplifier unit 5, and these components are integrated on the same substrate 11. The basic function of each component is the same as in FIG. That is,
It is configured to detect a change in magnetic coupling between the main magnetic pole 1 and the medium 6.

An exciting section 12 composed of an exciting core 1 'and an exciting coil 2
The medium 6 is configured to apply a high-frequency magnetic field to the entire medium 6. The high-frequency magnetic field acts more effectively on the medium near the main magnetic pole due to the magnetic field concentration effect of the main magnetic pole film 1 of the detection unit assembly 10.

In the configuration shown in FIG. 5, medium magnetization fluctuation is generated by the high-frequency magnetic field generated by the excitation unit 12, and the medium magnetization state is detected by the detection unit assembly 10 as a change in the main magnetic pole and the medium magnetic coupling.

〔The invention's effect〕

As described above, in the magnetic head according to the present invention,
Since the magnetization state of the magnetic recording medium can be easily detected as a change in the inductance of the main magnetic pole for detection or a change in the magnetic coupling between the main magnetic pole and the medium, reproduction sensitivity can be improved, and high-density track recording can be performed. And high linear density recording can be realized.

Further, the magnetic head of the present invention can be easily made into a multi-track head in addition to the simple structure, and a high transfer rate recording system for an image file or the like can be realized.

Further, as a magnetic recording medium, not only a perpendicular magnetization medium but also a longitudinal magnetization medium can be detected, and similar effects can be expected.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a configuration example of a magnetic head of the present invention, FIGS. 2 (a) and 2 (b) are explanatory diagrams of the principle of signal detection by the magnetic head of the present invention, and FIGS. 2 (b) is an equivalent circuit diagram corresponding to FIGS. 2 (a) and 2 (b), and FIGS. 4 and 5 are schematic structural diagrams of a magnetic head showing a specific embodiment of the present invention. . 1 ... Main magnetic pole, 2 ... Exciting coil, 3 ... Exciting power supply, 4 ... Detection coil, 5 ... Detection amplifier system, 6 ...
... Magnetic recording medium.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-58-122601 (JP, A) JP-A-58-48203 (JP, A) JP-A-1-196702 (JP, A) JP-A-63-1988 113902 (JP, A) JP-A-61-66203 (JP, A) JP-A-51-89412 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/02 G11B 5 / 127

Claims (2)

(57) [Claims] 1. A magnetic head for recording / reproducing information on / from a magnetic recording medium, comprising: a main magnetic pole for detection arranged close to the magnetic recording medium; and a coil for detection provided around the main magnetic pole. And GHz
An excitation coil that excites a high-frequency magnetic field of the order. After the magnetic recording medium is once subjected to magnetization oscillation by the high-frequency magnetic field of the excitation coil, a magnetic transition region in which coupling with the magnetic recording medium is strong is provided. By utilizing the fact that the main pole swings and the inductance changes due to the fluctuation, or the fact that the main pole and the medium magnetic coupling change in the magnetization transition region, the change in the magnetization state of the magnetic recording medium due to the above-mentioned magnetization fluctuation is obtained. And a change in the inductance, or a change in the main magnetic pole and the medium magnetic coupling, detected by the detection coil. 2. The magnetic head according to claim 1, wherein said magnetic recording medium is a perpendicular magnetic recording medium having magnetization regions in mutually opposite vector directions, and a high-frequency magnetic field excited by an exciting coil once detects a main magnetic pole for detection. A magnetic recording medium which is guided to a magnetic recording medium through the magnetic recording medium and causes a magnetic oscillation, particularly a magnetization transition region, of the magnetization in the perpendicular magnetic recording medium.