公开(公告)号：JPS62283482A

公开(公告)日：1987-12-09

申请号：JP12465686

申请日：1986-05-31

Applicant: CANON KK

Inventor： ODA HITOSHI ,  ONO TAKEO ,  KOBAYASHI TADASHI ,  NIIMI AKIRA

IPC: G11C11/14 ,  G11C19/08

Abstract: PURPOSE:To make a reproducing speed rapid and to simplify the constitution of a device by forming a high refractive index area in the vicinity of a magnetic domain and a surface, guiding polarization light flux into a magnetic film and detecting the passing light flux of a magnetic domain wall. CONSTITUTION:The divergent polarization light flux of a light source 22 is made parallel by a converging lens 24, incident on a light deflecting system 28, deflected, converged by a converging lens 25 and made incident on the end surface of the magnetic film 4. In the magnetic film 4, a stripe magnetic domain 6 having the magnetic domain wall 8 is formed, and in the vicinity of the surface, there is an area 6a of the higher refractive index than other part due to the diffusion of an iron ion or the like. The end of the strip magnetic domain is situated in the vicinity of the light incident end surface, the light flux is guided into a wave directing path through the magnetic domain wall of the end part and directed in the wave directing path. A rutileprism 30 disposed separately from the end part of the stripe magnetic domain takes out the guided light flux, converges 26 and makes incident on a light detector 32. Thereby, the end of the stripe magnetic domain is cut, a means for transferring a magnetic valve is not required to enhance a reproducing speed and simplify the constitution of the device.

公开(公告)号：JPH0447548A

公开(公告)日：1992-02-17

申请号：JP15670890

申请日：1990-06-14

Applicant: CANON KK

Inventor： KOBAYASHI TADASHI

IPC: G11B11/105 ,  G11B11/10

Abstract: PURPOSE:To obtain the magneto-optical recording medium suitable for use in a magnetic field modulating overwriting system by providing 1st and 2nd magnetic layers consisting of respectively specific rare earth/iron family amorphous alloys. CONSTITUTION:The 1st magnetic layer 4 is formed of the rare earth/iron family amorphous alloy which can be perpendicularly anodized, has a relatively low Curie temp. and relatively high coercive force at room temp. and has no compensation temp. between room temp. and the Curie temp. and in which the sub- lattice magnetization of the rare earths is dominant. The 2nd magnetic layer 3 is formed by using the rare earth/iron family amorphous alloy which has the Curie temp. higher than the Curie temp. of the high coercive force layer 4 and the low coercive force at room temp. and in which the sub-lattice magnetization of the iron family is dominant. This low coercive force layer 3 is exchangably bonded to the high coercive force layer 4 to each other. The bias magnetic field at the time of subjecting this medium to the recording by the magnetic field modulating overwriting system is decreased in this way.

公开(公告)号：JPH01213847A

公开(公告)日：1989-08-28

申请号：JP3753388

申请日：1988-02-22

Applicant: CANON KK

Inventor： KOBAYASHI TADASHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To improve the stability of recording information by using a rare earth-iron group amorphous alloy contg. Gd and Tb for a low-coercive force layer. CONSTITUTION:The low-coercive force layer consisting of exchangebonded two-layered films is constituted by using Gd-Tb-Fe, Gd-Tb-Fe-Co of the rare earth-iron group amorphous alloy contg. Gd and Tb. The magneto-optical recording medium which facilitates recording, improves the reading characteristic and is improved in the stability of the recording characteristic, more particularly the durability against the deterioration in information by reproducing light is obtd.

公开(公告)号：JPH01211343A

公开(公告)日：1989-08-24

申请号：JP3510588

申请日：1988-02-19

Applicant: CANON KK

Inventor： KOBAYASHI TADASHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To enable the independent control of the intensity of an exchange bond and coercive force by providing a 3rd magnetic layer which is a perpendicularly magnetized film having the magnetic wall energy smaller than the magnetic wall energy of 1st and 2nd magnetic layers between said magnetic layers. CONSTITUTION:The 3rd magnetic layer which is the perpendicularly magnetized film having the magnetic wall energy relatively smaller than the magnetic wall energy of the 1st magnetic layer and 2nd magnetic layer of the exchange bond two-layered films which allow overwriting by modulation of a laser power is provided between the 1st and 2nd magnetic layers. The magnitude of the magnetic wall energy at the boundary and eventually the intensity of the exchange bond acting between the 1st and 2nd magnetic layers are, therefore, controlled by changing the film thickness of the 3rd magnetic layer even if the kinds of the rare earths of the 1st and 2nd magnetic layers are not changed. The independent control of the intensity of the exchange bond and the coercive force is thereby enabled.

公开(公告)号：JPS63117355A

公开(公告)日：1988-05-21

申请号：JP26262986

申请日：1986-11-06

Applicant: CANON KK

Inventor： KOBAYASHI TADASHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To optimize recording and reproducing characteristics of information by using thin amorphous alloy films of a rare earth-iron family in which the magnetization of the sub-lattice of the iron family is dominant as a recording layer and reading-out layers and paralleling the directions of the net magnetizations of the three layers. CONSTITUTION:The thin amorphous films of the rare earth-iron family in which the magnetization of the sub-lattice of the iron family is dominant are used as the recording layer 2 and both reading-out layers 1, 3 of the medium for a magneto-optical memory having the magnetic layer of the three-layered structure in which the recording layer 2 having the high coercive force at a room temp. and low Curie temp. is sandwiched and exchange-coupled by the reading- out layers 1, 3 having the low coercive force and high Curie temp. In addition, the directions of the net magnetizations of the three layers are paralleled. Tb-Fe, Dy-Fe, Gd-Tb-Fe, Gd-Dy-Fe, Tb-Dy-Fe, Tb-Fe-Co, Dy-Fe-Co, Gd-Tb-Fe-Co, Gd-Dy- Fe-Co, Tb-Dy-Fe-Co, etc., or those added with Cr and Al, etc., are preferable as the recording layer. Gd-Fe, Gd-Fe-Co, Gd-Co, etc., or those added with Cr, Al, etc., are preferable for the reading-out layers. The recording and reproducing characteristics are thereby optimized.

公开(公告)号：JPS6363156A

公开(公告)日：1988-03-19

申请号：JP20583686

申请日：1986-09-03

Applicant: CANON KK

Inventor： KOBAYASHI TADASHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To heighten erasing sensitivity utilizing a floating magnetic field made by magnetization of a magnetic layer of a non-recording area by reversing the direction of magnetization of magnetic layers of a recording area and a non-recording area of a medium for magneto-optical memory, and then making magneto-optical recording. CONSTITUTION:After manufacturing a medium, a magnetic field of above coercive force of the medium is applied upward in the figure over whole face of the medium for initializing, and further, the direction of magnetization of the magnetic layer on a non-recording groove 1 is reversed using laser light and magnetic field. It can be controlled freely to make the light beam trace the crest of the groove or trace the bottom of the groove by inverting the phase of an error signal of tracking. Then, the recording and erasing operation is performed next. The direction of a floating magnetic field made by the magnetic layer on the non-recording groove 1 on the recording layer 2 is upward and works in the direction to help erasing. Accordingly, the magnitude of laser power and bias magnetic field at the time of erasing information becomes small.

公开(公告)号：JPS6318544A

公开(公告)日：1988-01-26

申请号：JP15972286

申请日：1986-07-09

Applicant: CANON KK

Inventor： KOBAYASHI TADASHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To improve exchange bond together with recording characteristics and corrosion resistance by using Tb-Fe-M (M=Cr or Al) for a recording layer and Gd-Fe-Co for a reading out layer. CONSTITUTION:The recording layer of this medium for a magneto-optical memory having a magnetic film of the two-layered structure making the exchange bond consisting of the recording layer having high coercive force and low Curie temp. at a room temp. and the reading out layer having low coercive force and high Curie temp. consists of Tb-Fe-M and the reading out layer thereof consists of Gd-Fe-Co. (M is an element selected from Cr and Al). The elevation of the Curie temp. is suppressed and the corrosion resistance is improved without degrading the recording sensitivity by adding the Cr and Al to the recording layer.

公开(公告)号：JPS6316444A

公开(公告)日：1988-01-23

申请号：JP15971886

申请日：1986-07-09

Applicant: CANON KK

Inventor： KOBAYASHI TADASHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To obtain a medium for a magneto-optical memory having improved recording characteristics by using Tb-Dy-Fe for a recording layer and Gd-Fe-Co for a reading out layer. CONSTITUTION:This medium is formed by having the recording layer having the two-layered structure making the exchange bond consisting of the recording layer having high coercive force at a room temp. and low Curie temp. and the reading out layer having low coercive force and high Curie temp. The recording layer consists of Tb-Dy-Fe and the reading out layers consist of Gd-Fe-Co. Various auxiliary layers such as reflective layer to making effective use of light and protective layer for improving the protective function by protecting the magnetic layer are disposed in addition to the magnetic layer to the medium. The medium for the magneto-optical memory having the improved recording characteristics is thus obtd.

公开(公告)号：JPS6316442A

公开(公告)日：1988-01-23

申请号：JP15971686

申请日：1986-07-09

Applicant: CANON KK

Inventor： KOBAYASHI TADASHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To improve recording characteristics, corrosion resistance and exchange bond by using R-Fe-Co (R=Tb and/or Dy) for a recording layer and Gd-Fe-Co for reading out layers and sandwiching the recording layer with the reading out layers. CONSTITUTION:This medium is formed by having the recording layer having the three-layered structure making the exchange bond by sandwiching the recording layer having high coercive force at a room temp. and low Curie temp. with the reading out layers having low coercive force and high Curie temp. The recording layer consists of R-Fe-Co and the reading out layers consist of Gd-Fe-Co. R is 1 or 2 kinds of the elements selected from Tb and Dy. Not only the change in the lapse of time of the medium but the exchange bond as well are improved by using the recording layer improved in the corrosion resistance in the above-mentioned manner.

公开(公告)号：JPS6314342A

公开(公告)日：1988-01-21

申请号：JP15718586

申请日：1986-07-05

Applicant: CANON KK

Inventor： SASAMORI EIZO ,  KOBAYASHI TADASHI

IPC: G11B11/10 ,  G11B11/105

Abstract: PURPOSE:To increase sensitivity while maintaining a high reproducing characteristic by providing a writing layer and reading-out layer onto a substrate, forming the writing layer to >=50Angstrom thickness and to the thickness smaller than the thickness of the reading-out layer. CONSTITUTION:This recording medium is formed by having a high-coercive force layer (writing layer) 4 exhibiting a low Curie point and a low-coercive force layer (reading-out layer) 3 exhibiting the low Curie point on the substrate 1. The writing layer 4 is formed to >=50Angstrom thickness and to the thickness smaller than the thickness of the reading-out layer 3. For example, the thickness of the reading-out layer 3 is preferably about 300-600Angstrom and the thickness of the writing layer 4 about 100-400Angstrom if the reading-out layer 3 and the writing layer 4 both consist of an amorphous magnetic alloy of a rare earth element and reducing element. The decrease of the power necessary for recording is permitted without deteriorating the reproducing characteristic by forming the writing layer 4 to the thickness smaller than the thickness of the reading-out layer 3 and decreasing the film thickness over the entire part of the magneto- optical recording layer.