Other

Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Yuuko Kawaguchi

Motoyoshi Murakami

Shinya Abe

Eiji Ohno

Masahiro Birukawa

Morio Tomiyama

Tsutomu Shiratori

Yasuyuki Miyaoka

An optical recording medium is provided with: a first substrate having first pits on one face thereof; a first reflective layer that is formed on the face bearing the first pits of the first substrate in a manner so as to reflect lands and recesses of the first pits; a second substrate that is formed on the first reflective layer, with second pits being formed on a face on the side opposite to the first reflective layer; a second reflective layer that is formed on the face bearing the second pits of the second substrate in a manner so as to reflect lands and recesses of the second pits; and a cover layer formed on the second reflective layer. In this structure, the first pit depth dthat is a difference between lands and recesses of the first reflective layer, the wavelength &#x3bb; of signal-reproducing laser light and the refractive index nof the second substrate satisfy the following relational expressions: &#x3bb;/(5n)&#x2266;d&#x2266;&#x3bb;/(3n) and d&#x2260;&#x3bb;/(4n). Moreover, the second pit depth d, which is a difference between lands and recesses of the second reflective layer, the wavelength &#x3bb; of signal-reproducing laser light and the refractive index nof the cover layer satisfy the following relational expressions: &#x3bb;/(5n)&#x2266;d&#x2266;&#x3bb;/(3n) and d&#x2260;&#x3bb;/(4n).

Optical recording medium and process for producing the same

A multilayer film including a first magnetic layer, a second magnetic layer, and a third magnetic layer in the stated order is formed so that a Curie temperature T of the second magnetic layer is set to be lower than a Curie temperature T of the first magnetic layer and a Curie temperature T of the third magnetic layer and that the third magnetic layer is a perpendicular magnetization film. In at least a part of a region at a temperature lower than T , the first magnetic layer is perpendicularly magnetized by exchange coupling with the second magnetic layer, and the magnetization of the third magnetic layer is transferred to the first magnetic layer via the second magnetic layer because of the exchange coupling. The second magnetic layer is made of a magnetic layer that remains in an in-plane magnetization state at room temperature and is perpendicularly magnetized in a temperature range from a critical temperature T higher than room temperature to the Curie temperature T of the same. Thus, in a magneto-optical recording medium to which the magnetic-domain enlarging-reproducing method is applied, upon reproduction of information utilizing the magnetic-domain enlargement, magnetic influences from tracks adjacent to a target track are suppressed.

Magneto-optical recording medium having multiple magnetic layers

By irradiating a light beam between recording tracks of the magneto-optical recording medium, the magnetic anisotropy of at least one layer selected from the group consisting of the domain wall displacement layer and the recording layer formed between the recording tracks can be made lower than that of said layers on the recording tracks, and a bias magnetic field is applied at least between recording tracks while a light beam is radiated. Because of this, initialization of a medium may be conducted simultaneously.

Magneto-optical recording medium, and method and apparatus for producing the same

Growing community of inventors

Osaka, Japan

Yuuko Kawaguchi