JP2867754B2 - Magneto-optical recording medium and recording method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium and a recording method thereof, and more particularly to a light modulation overwrite medium and a recording method thereof.

[0002]

2. Description of the Related Art In a conventional optical modulation overwrite magneto-optical recording / reproducing apparatus, a bias magnetic field is applied to a permanent magnetic head which is opposed to an optical head, located on the back side of a disk substrate, or integrated with the optical head. They were given by magnets or electromagnets.

[0003]

In a conventional light modulation overwrite magneto-optical recording / reproducing apparatus, a bias magnetic field is
When the optical head is opposed to the optical head, it is difficult to access the optical head from both sides by facing the two optical heads. Further, when the bias magnetic field is generated by the magnet integrated with the optical head, there is a problem that the weight of the head is increased and the access is slowed.

[0004] An object of the present invention is to provide a magneto-optical recording medium and a recording method for solving the above problem.

[0005]

The magneto-optical recording medium of the present invention comprises at least two magnetic layers having perpendicular anisotropy, one of which is a recording layer and the other of which is an auxiliary layer. Overwritable recording film, provided on the light intensity modulation overwritable recording film via a thermal insulating layer,
It is characterized by comprising a bias magnetic field generating layer having perpendicular anisotropy, and a bias magnetic field enhancing layer adjacent to the bias magnetic field generating layer and having in-plane anisotropy.

A recording method for a magnetic recording medium according to the present invention uses a magneto-optical recording medium according to the present invention, and does not require a magnetic field from an external bias magnet at a laser beam irradiation position.
Laser beam irradiation in the recording method of air recording media
When the auxiliary layer is not
A first direction in which the recording layer is aligned in a fixed direction independently of the magnetization direction.
Steps and the power of the irradiating laser beam are recorded
Depending on the information you want to correspond to low level and high level
At the time of the low level laser beam irradiation.
The magnetization of the auxiliary layer is transferred to the recording layer,
When irradiating a high level laser beam, the via
Magnetic field generated by the magnetic field generation layer and the bias magnetic field enhancement layer
A second step for magnetizing the recording layer in the
And a pump .

[0007]

According to the present invention, the magnetic field generated by the bias magnetic field generation layer and the bias magnetic field enhancement layer of the medium is used as the bias magnetic field for light intensity modulation overwritable recording. Therefore, conventionally
To generate a bias magnetic field,
There is no need for integrated permanent magnets or electromagnets.
There is no need to generate a bias magnetic field at the irradiation position.
As a result, simultaneous access to both sides is facilitated. The bias magnetic field generation layer is a perpendicular magnetization layer having a high coercive force, a high Curie temperature and a large magnetization, and is magnetized in one direction in advance. The bias magnetic field enhancement layer is an in-plane magnetization film, is adjacent to the bias magnetic field generation layer, and serves to enhance the static magnetic field generated by the bias magnetic field generation layer.

[0008]

FIG. 1 is a schematic sectional view of an embodiment of a magneto-optical recording medium according to the present invention. This magneto-optical recording medium was manufactured as follows.

On a PC substrate 1, a protective film 2 of a silicon nitride film is 800 angstroms, a recording layer 3 of TbFeCo is 400 angstroms, a control layer 4 of a GdFeCo film is 150 angstroms, and GdTbFe.
1000 Å of the auxiliary layer 5 made of a Co film,
A thermal insulating layer 6 of a silicon nitride film containing hydrogen was laminated in order of 400 Å, a bias magnetic field generating layer 7 made of TbCo was 1500 Å, and a bias magnetic field enhancement layer 8 made of NiFe was laminated in 300 Å. The recording layer 3 had a TM-rich composition, and the auxiliary layer 5 had an RE-rich composition.

The recording layer 3, the control layer 4, and the auxiliary layer 5 constitute a light intensity modulation overwritable recording film.

Next, an embodiment of the recording system of the present invention will be described with reference to FIG. As the magneto-optical recording medium, a double-sided bonded medium 13 in which the medium described in FIG. 1 is bonded with the bias magnetic field enhancement layers 8 facing each other is used. 9 is a bonding layer.

Using this double-sided bonded medium 13, overwriting and reproduction were performed with a magneto-optical disk device having a leading magnetic field of 3 kOe and no external bias magnet.
The leading magnetic field was created by the permanent magnet 11. The magnetization of the bias magnetic field generation layer 7 was initialized in advance after film formation, and aligned in one direction. The head (not shown) faces the medium 13,
Simultaneous overwrite access was performed on both sides by irradiation with the laser beam 10. Operating in parallel doubled the transfer rate.

In the present embodiment, the method of forming a preceding magnetic field by using a permanent magnet has been described, but it is also possible to use an electromagnet. As the medium, an example of the TM-rich recording layer and the RE-rich auxiliary layer has been described, but the medium is not limited thereto. For example, T
Good characteristics can be obtained even with M-rich, TM-rich, and the like. Accordingly, the magnetization directions of the leading magnetic field and the bias magnetic field generating layer are determined so as to be suitable for overwriting. In the case of the former, the direction is the same, and in the case of the latter, the direction is reversed.

[0014]

As described above, the present invention provides a conventional battery pack.
No permanent magnets or electromagnets are required to generate the ias magnetic field
is there. Therefore, the heads are opposed to each other to facilitate simultaneous access on both sides, and the data transfer rate can be doubled.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one embodiment of a magneto-optical recording medium of the present invention.

FIG. 2 is a diagram for explaining a recording method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Protective film 3 Recording layer 4 Control layer 5 Auxiliary layer 6 Thermal insulation layer 7 Bias magnetic field generation layer 8 Bias magnetic field enhancement layer 9 Disk bonding layer 10 Laser beam 11 Permanent magnet which creates a preceding magnetic field

Claims (2)

(57) [Claims] 1. A light intensity modulation overwriteable recording film comprising at least two magnetic layers having perpendicular anisotropy, one of which is a recording layer and the other is an auxiliary layer. A bias magnetic field generation layer having perpendicular anisotropy provided on the recording film with a thermal insulating layer interposed therebetween, and a bias magnetic field enhancement layer having in-plane anisotropy adjacent to the bias magnetic field generation layer A magneto-optical recording medium characterized by the following. 2. A magnetic field from an external bias magnet at a laser beam irradiation position using the magneto-optical recording medium according to claim 1.
In a recording method for a magneto-optical recording medium
When the beam is not irradiated,
The magnetization of the auxiliary layer is constant independently of the magnetization direction of the recording layer
The first step of aligning the direction and the laser beam to be irradiated
Low and high according to the information you want to record
The low level laser beam corresponding to the level
At the time of irradiation, the magnetization of the auxiliary layer is transferred to the recording layer.
So that the high level laser beam irradiation
The bias magnetic field generating layer and the bias magnetic field enhancement
So that the recording layer is magnetized in the direction of the magnetic field generated by the layer.
A recording method for a magneto-optical recording medium.