JPH0664681B2 - Magnetic recording / reproducing method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perpendicular magnetic recording / reproducing method, and more particularly to a method for enabling operation of a magnetic head suitable for high density recording.

[Background of the Invention]

Although various reports have been made on the characteristics when recording and reproducing are performed on a perpendicular recording medium with a ring head, the results of sufficient examination of the relationship between the recording current and the recording density characteristics have not been published yet. The conditions for recording sufficiently in the high recording density region throughout the thickness of the recording medium have not always been clear.

In the past, for example, the 7th Japan Applied Magnetics Society Academic Lecture Summary
As shown in 9aA-4 (p203) and the like, recording was performed on a perpendicular recording medium at a constant current value regardless of the recording density.

[Object of the Invention]

An object of the present invention is to provide a method capable of sufficiently recording on a medium up to a high recording density.

[Outline of Invention]

As a result of changing the recording current flowing in the head and changing the recording state of the medium to obtain the recording / reproducing output, in the case of perpendicular magnetic recording, the signal in the high density area is low in recording unlike the case of conventional longitudinal recording. It has been found that, by recording a signal in a low density region with a current at a high recording current, sufficient recording can be performed up to a very high recording density.

Example of Invention

FIG. 1 shows the recording density characteristics when recording and reproducing with a ring head on a Co-Cr perpendicular magnetization medium. The medium was Co-coated on the Pyrex glass substrate with a thickness of about 0.35 μm by the sputtering method.
Coated with Cr thin film, vertical coercive force Ho ₁ ~ 5000
e, saturation magnetization Ms ~ 300emu / cc. Ring head is Mn−
This is a winch-ester type head made of Zn ferrite polycrystal and having a winding number of 7 + 7T and a gear length g ₁ = 0.25 μm. If the recording current I _w is increased to 20 mAop and 30 mAop, it will be several 10 KFCI.
It can be seen that the output becomes smaller in the above high recording density region. This tendency is a common feature when recording and reproducing are performed on a perpendicular magnetization medium, especially a Co-Cr perpendicular magnetization medium by using a ring head.

When actually used as a device, a new signal may be recorded on a previously recorded signal, but since the previously recorded signal becomes noise unless it is sufficiently erased by the new signal, the signals are superimposed. Characteristics when written (generally Over W
rite characteristics, O / W) become a problem. The O / W is generally expressed as the ratio of the recorded / reproduced output of the previous signal to the recorded / reproduced output of the new signal.

FIG. 2 (a) shows O / W when a 70KFCI signal is recorded on a 32KFCI signal, and (b) shows O / W when a 32KFCI signal is recorded on a 70KFCI signal. Generally, in order for the device to operate, it is necessary to be O / W-26 dB or less, but in order to satisfy this, in the case of (a), the recording current Iw is about 20 mA or more,
In case of (b), it should be 30mA or more. In general, when recording and reproducing by combining a ring head with a perpendicular magnetization medium, in order to satisfy O / W, it is better to record a signal with a low recording density on a signal with a higher recording density to achieve a higher recording on a signal with a lower recording density. It can be seen that a large recording current is required rather than recording a signal of density.

From the above results, it is necessary to make the recording current relatively small in order to extend the recording density characteristic to the high density side, and it is necessary to increase the recording current at least at the time of recording at the low recording density in order to improve the O / W. .

In the embodiment, the recording current is 30 mA when the recording density is 50 KFCI or less.
As a result of recording at a recording current of 20 mA at 50 KFCI or more, the device could be operated at a recording density of 80 KFCI.
When the recording current is kept constant at 30 mA in the entire recording density region, the device can be operated only at 60 KFCI, and the effect of the present invention is remarkable.

〔The invention's effect〕

According to the present invention, sufficient recording can be performed on a recording medium up to a high recording density area, so that a compact and high-density storage device can be realized.

[Brief description of drawings]

1 and 2 are characteristic diagrams for explaining the present invention.

Claims (2)

[Claims] 1. A method for performing recording / reproducing on a perpendicular magnetization medium, wherein a ring head is used as a magnetic head for recording on a perpendicular magnetization medium, and recording is performed by changing a recording current flowing through the head according to a recording density. Magnetic recording / reproducing method characterized in that a recording current used for recording a signal having a recording density higher than the recording density is lower than a recording current used for recording a signal having a recording density lower than a predetermined recording density. . 2. A magnetic recording / reproducing method according to claim 1, wherein the perpendicular magnetization medium has at least a part of an alloy containing Co--Cr as a main component.