JPH0474764B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to perpendicularly magnetized magnetic heads.

Perpendicular magnetic recording is known to have excellent high-density recording characteristics, and research and development are being actively conducted.
A head for perpendicular magnetic recording and reproduction needs to generate a magnetic field perpendicular to the surface of the magnetic recording medium to perform recording, and for this purpose a magnetic thin film is placed perpendicular to the surface of the magnetic recording medium for recording. A so-called single magnetic pole head has been proposed and is known to exhibit excellent recording and reproducing characteristics. However, single-pole heads have drawbacks such as lower reproduction sensitivity than ring heads because the magnetic path is not closed, and susceptibility to external noise. Attempts have been made in various fields to perform perpendicular magnetic recording and reproduction using a circular ring head, and it is known that magnetic recording media have excellent characteristics if they have ideal perpendicular anisotropy. However, manufacturing an ideal perpendicular magnetic recording medium has drawbacks such as high manufacturing costs.

The present invention has been made in view of this point,
It operates in the same way as a single-pole head during recording, generating a sharp perpendicular magnetic field, and operates in the same way as a ring head during playback, providing a head with high playback sensitivity and little influence from external noise. A detailed explanation will be given below using the drawings.

FIG. 1 shows a commonly used single magnetic pole head, in which a main magnetic pole 1 and an auxiliary magnetic pole 2 are disposed facing each other with a medium consisting of a perpendicularly magnetized film 4 and a base 5 interposed therebetween. The main pole 1 is made of a magnetic thin film with high magnetic permeability. The auxiliary magnetic pole 2 is made of ferrite material or the like, and a coil 12 is wound around it. When a recording current is supplied from the terminals 3 and 3', a magnetic field is generated by the coil 12, and the lines of magnetic force 6 are concentrated at the tip of the main magnetic pole 1 rather than the auxiliary magnetic pole 2. Recording is achieved by magnetizing the perpendicular magnetization film 4 of the medium by these sharp lines of magnetic force.

Further, FIG. 2 is a modification of FIG. 1, in which recording is attempted from one side of the medium. That is, the main magnetic pole 1 is attached to the auxiliary magnetic pole 2, and the coil 1 is placed on top of it.
The purpose is to generate sharp lines of magnetic force at the tip of the main magnetic pole 1 by winding the main magnetic pole 1 and passing a recording current through the terminals 3 and 3'. During reproduction, both the head shown in FIG. 1 and the head shown in FIG. A voltage proportional to the magnetic flux interlinked with terminal 3,
It is generated at 3'. The drawbacks of such a single magnetic pole head are that since the magnetic path is an open magnetic path, it is easily affected by noise electromagnetic waves from outside, the reproduction voltage is low, and a good signal-to-noise ratio cannot be obtained.

FIG. 3 shows a ring head, and the ring core 7 is provided with a gap 11 on the surface that contacts the medium. When a recording current is passed through the coil 12 of the ring head from the terminals 3, 3', magnetic lines of force 6'' are generated in the gap 11, and the perpendicular component of the lines of magnetic force 6'' causes perpendicular magnetization. However, the lines of magnetic force generated by the gap 11 have many horizontal components,
If the perpendicularly magnetized film does not have ideal perpendicular anisotropy, excellent characteristics cannot be obtained. Although it is possible to create an ideal perpendicularly magnetized film on a laboratory scale under specific production conditions, it is difficult and impractical when attempting to mass-produce media. The present invention has been made in view of this point.

FIG. 4 shows one embodiment of the present invention, which has a ring-shaped structure made up of cores 8, 8' and 9, and a gap 11 is provided on the surface that contacts the medium. The cores 8, 8' are made of a magnetic material having a sufficiently large cross-sectional area so as not to cause magnetic saturation when a recording current is passed through the coils 12, 12'. Further, the core 9 is made of a magnetic material that has high magnetic permeability and a small cross-sectional area, or has low saturation magnetization. Wind the coils 12, 12' around this head 2
By turning the two-pole contact switch 13 to the A and A' sides and allowing current to flow from the recording signal generator 14 to the coils 12 and 12', the cores 8 and 8' are magnetized in the same direction, and the core 9 is also magnetized. It easily becomes magnetically saturated and ends up with vertical sharp lines of magnetic force 6 in the gap 11.
occurs, and the perpendicularly magnetized film 4 of the medium has the following characteristics as shown in FIGS.
Recording can be done in the same way as explained in the figure. Regarding reproduction, as shown in FIG. 5, the magnetic lines of force in the perpendicularly magnetized film of the medium enter the core 8 through the gap 11, pass through the core 9, and return to the perpendicularly magnetized film via the core 8'. Since the amount of magnetic flux passing through the core 9 at this time is minute, the design is such that magnetic saturation does not occur. Therefore, by inducing voltage in the coils 12 and 12' and turning the switch 13 to the B and B' sides, the reproduced signal is input to the amplifier 15 and can be extracted at the required voltage.

As is clear from the above explanation, since the present invention operates in the same way as a ring head during playback,
It provides excellent characteristics such as high sensitivity, which is a characteristic of ring heads, and is less susceptible to external noise electromagnetic waves. Furthermore, since the perpendicular magnetic recording medium performs the same operation as a single magnetic pole head during recording, the perpendicular anisotropy of the perpendicular magnetic recording medium does not need to be ideal.

FIG. 6 shows another embodiment of the present invention, in which the core 8,
High permeability magnetic thin films 10, 10' are attached along the inside of the gap 11 up to the tip of the gap 11, and these magnetic thin films 10, 10' serve to improve efficiency during recording and reproduction.

As explained above, the head of the present invention has extremely excellent characteristics. Furthermore, the embodiment described above is just one example, and it is obvious that modifications such as modifying the shape of the core and switching between recording and reproduction electronically instead of using a switch are possible.

[Brief explanation of the drawing]

1 and 2 are diagrams showing a typical example of a conventional single magnetic pole head, FIG. 3 is a diagram showing a typical example of a conventional ring head, and FIG. 4 is a diagram showing a typical example of a conventional ring head during recording. FIG. 5 is an explanatory diagram of the head of the present invention during regeneration, and FIG. 6 is a diagram showing another embodiment of the present invention. 1...Main magnetic pole, 2...Auxiliary magnetic pole, 3,3'...
Coil terminal, 4... Perpendicular magnetization film, 5... Base body,
6, 6', 6'', 6... Line of magnetic force, 7... Ring core, 8, 8', 9... Core, 10, 10'... High permeability magnetic thin film, 11... Gap, 12, 1
2'... Coil, 13... Switch, 14... Recording signal generator, 15... Amplifier.

Claims (1)

[Claims] 1. A part of the core of the perpendicularly magnetized ring head is located on the opposite side of the recording/reproducing gap, and is magnetically saturated depending on the magnetic flux generated by the recording current during recording.
A core part that is not magnetically saturated by the magnetic flux generated during reproduction is provided, a current coil is wound around each of the two core parts between the core part and the gap, and the recording signal is generated using the two current coils. During recording, a current is passed from the recording signal generator to generate magnetic poles of the same polarity on both sides of the gap, and during reproduction, the two coils are connected in series and the two ends are connected to each other. A perpendicularly magnetized magnetic head characterized in that it is equipped with a switch circuit that serves to connect to a reproduction signal amplifier.