Abstract: A magnetic recording medium having a recording layer made up of a ferrimagnetic material whose compensation temperature is included within room temperatures and an information recording-reproduction method using the magnetic recording medium. During recording, while a light beam is projected on the recording layer so as to raise the temperature of a recording portion, information is recorded by applying a signal magnetic field from a magnetic head. During reproduction, while a light beam is projected on a reproducing portion of the recording layer so as to raise the temperature thereof, information is reproduced by detecting leakage flux from the reproducing portion by the magnetic head. Thus, during reproduction, no magnetic flux is generated from other portions of the recording layer not irradiated by the light beam. With the arrangement, crosstalk due to leakage flux from adjoining tracks not irradiated by the optical beam can be eliminated.

Abstract: In an optical disk, grooves and lands serving as recording tracks are provided, the grooves are shaped so as to have virtually the same width, and in a first region, the two side walls of each groove wind in accordance with address information. The first region of the groove is formed with its leading portion located at the same angular position as the leading portion of at least one of the first regions of the adjacent grooves. Moreover, the winding portions corresponding to respective bits of the address information are formed in a manner so as to synchronize to the adjacent grooves. With this arrangement, it becomes possible to easily detect address information from the grooves and lands, and consequently to obtain an information reproducing signal with high quality.

Abstract: A recording layer and a flux adjustment layer have different magnetic polarities so that their magnetizations are countervailed at room temperature, with the result that a weakened leakage magnetic flux is released therefrom. A reproducing layer, a reproducing assist layer and an in-plane magnetization layer exhibit in-plane magnetization at room temperature. In a first temperature area having a temperature not more than the critical temperature of the reproducing layer, the reproducing layer 1 exhibits in-plane magnetization so that magnetization of a recording magnetic domain is not copied to the reproducing layer.

Abstract: Grooves and lands are provided to a magneto-optical disk so as to be alternately arranged, and recording bit strings are formed on the grooves and lands respectively so that information is recorded. Moreover, pit rows are formed on boundary sections between the adjoining grooves and lands so that address information of a recording/reproducing track is recorded, and the pit rows are formed every other boundary section. When the grooves and the lands are scanned as the recording/reproducing track by a light, an address of the recording/reproducing track is read out from the pit rows, and successively, discrimination is made whether the recording/reproducing track which is scanned by an optical spot is the groove or the land. This prevents crosstalk which causes inclusion of address information in the next pit rows, thereby, making it possible to obtain accurate address information.

Abstract: An magneto-optical recording medium includes: a transparent dielectric layer; a reproduction layer that is in an in-plane magnetization state at room temperature and changes into a perpendicular magnetization state with a rise in temperature; a non-magnetic intermediate layer; a recording layer made of a perpendicularly magnetized film; and a protection layer, the layers being formed one after another in this order. The recording layer is made of a rare-earth and transition metal alloy, and the rare earth metal is composed of more than two kinds of rare-earth-metal elements containing Gd. The information stored in a magnetic recording domain is masked with respect to a part that is in an in-plane magnetization state. Consequently, recording can be performed with a less powerful laser beam, and each recording bit can be reproduced independently to produce high quality signals even if the converged light beam covers a neighboring recording bit within its radius.

Abstract: An optical disk has address recording sections each of which has a wobbled part of one of side walls of a groove. Each address recording section is formed by providing convexes of a groove in an adjacent land so as to widen the groove. With the wobbles thus provided in a concavo-convex form, address information is recorded. Besides, the address recording sections thus provided in the grooves are linearly disposed in radial directions of the optical disk. By thus arranging the optical disk on whose grooves and/or lands information is recorded, mixing of wobble frequency components in reproduced information signals does not occur, the sector method is applicable to the optical disk, and information signals of high quality can be obtained.

Abstract: A magneto-optical recording disk includes a recording layer for recording information as a mark and a reproduction layer, laminated with the recording layer, to which magnetization direction of the recording layer is transferred at high temperatures, wherein the reproduction layer and the recording layer are magnetostatically coupled and are not exchange-coupled. The information is read out by using a temperature distribution generated by a light beam for reproduction. The recording layer has, on a side thereof to which the reproduction layer is not provided, a supplementary back layer of a soft magnetic material composed of ferromagnetic material. The magneto-optical disk is designed to generate good CNR and thereby improves recording density even when a short mark is reproduced.

Abstract: A magneto-optical recording medium including at least a recording layer, and an auxiliary recording layer which achieves magnetostatic coupling with the recording layer. The auxiliary recording layer is in an in-plane magnetization state at temperatures lower than a recording temperature, and in a perpendicular magnetization state at temperatures not lower than the recording temperature. It is therefore possible to achieve a decrease in a recording magnetic field.

Abstract: An optical probe element for focusing light from a light source into micro light of a diameter not larger than the diffraction limit, includes a light transmitting flat substrate and an optical probe formed on one of the surfaces of the flat substrate. The optical probe has a substantially conical light transmitting projection, and a reflective film which covers the conical surface of the projection so that the tip of the projection is exposed. The optical probe element enables the optical probe to be formed on the flat substrate using a semiconductor processing technique, thereby achieving efficient mass production of a standardized optical probe element. Thus, a recording and reproduction apparatus using the optical probe element is efficiently mass-produced.

Abstract: A magneto-optical recording medium includes first, second, and third magnetic layers laminated in this order. The first magnetic layer, made of a rare earth-transition metal alloy, has a great coercive force at room temperature and is transition metal rich in a temperature range between room temperature and a Curie temperature of the first magnetic layer. The second magnetic layer, made of a rare earth-transition metal alloy, has a Curie temperature higher than that of the first magnetic layer and is rare-earth metal rich at room temperature. The third magnetic layer, made of a rare earth-transition metal alloy, has a Curie temperature higher than that of the first magnetic layer, and a compensation temperature falling in a temperature range between room temperature and the Curie temperature of the third magnetic layer. A magnetization of the third magnetic layer is transferred to the first magnetic layer at a temperature higher than room temperature. A perpendicular magnetic anisotropy Ku3 satisfies 0.3.

Abstract: A magneto-optical recording medium with a reproducing layer that exhibits in-plane magnetization at room temperature and that comes to exhibit perpendicular magnetization as temperature rises. The second shielding layer is used to block the magnetization of record bits other than a record bit to be reproduced from being copied on a signal reproducing area in the reproducing layer. Consequently, even in the case of high-density record bits in the recording layer, only the magnetization of the record bit to be reproduced is copied on the reproducing layer. Therefore, the application of the magneto-optical recording medium makes it possible to produce superior reproducing signals even in the case where the records bits with high density are formed on the recording layer.

Abstract: A super-resolution magneto-optical recording medium has a reproducing layer, an in-plane magnetization layer and a recording layer. The reproducing layer and the recording layer are magnetostatically coupled, and each of the layers is made of a rare-earth transition-metal alloy which has a greater transition-metal sublattice moment than the compensation composition, and exhibits perpendicular magnetization, if it exists alone. At a temperature not more than the Curie temperature, the in-plane magnetization layer is exchange-coupled with the reproducing layer so as to allow the reproducing layer to exhibit in-plane magnetization. Since the reproducing layer is allowed to exhibit in-plane magnetization by the in-plane magnetization layer, it is not necessary to use a material containing a greater rare-earth metal sublattice moment as the reproducing layer.

Abstract: A magneto-optical recording medium includes a reproducing layer which has in-plane magnetization at room temperature and has perpendicular magnetization at an elevated temperature of not less than a critical temperature, a recording layer made of a perpendicular magnetization film for recording information, an intermediate layer made of a non-magnetic film formed between the reproducing layer and the recording layer, and an in-plane magnetization layer adjacent to the reproducing layer, in which magnetization is reduced at a temperature in a vicinity of the critical temperature. According to the described magneto-optical recording medium, since information recorded in a recording magnetic domain of a portion having the in-plane magnetization is masked, even in the case where adjacent recording bits fall within a diameter of a spot of a converged light beam, each recording bit can be reproduced separately, thereby obtaining a quality reproduced signal.

Abstract: If the Curie points of the first magnetic layer, second magnetic layer, third magnetic layer and fourth magnetic layer of alloys of rare-earth metal and transition metal as ferrimagnetic materials showing perpendicular magnetization from room temperature to their Curie points are indicated as Tc1, Tc2, Tc3 and Tc4, respectively, the Curie points and room temperature are related by: room temperature<Tc3<Tc4<Tc1<Tc2. If the sublattice magnetization of transition metal is indicated as .alpha. and the sublattice magnetization of rare-earth metal is .beta., .alpha. is stronger than .beta. in the second magnetic layer at temperatures between Tc1 and Tc2, and .beta. is stronger than .alpha. in the fourth magnetic layer at temperatures between room temperature and Tc4.

Abstract: An optical disk has address recording sections each of which has a wobbled part of one of side walls of a groove. Each address recording section is formed by providing convexes of a groove in an adjacent land so as to widen the groove. With the wobbles thus provided in a concavo-convex form, address information is recorded. Besides, the address recording sections thus provided in the grooves are linearly disposed in radial directions of the optical disk. By thus arranging the optical disk on whose grooves and/or lands information is recorded, mixing of wobble frequency components in reproduced information signals does not occur, the sector method is applicable to the optical disk, and information signals of high quality can be obtained.

Abstract: A magneto-optical recording medium according to the present invention comprises a recording layer in which information is to be recorded; and a reproducing layer to and from which information recorded in the recording layer is to be transferred and read out. The magneto-optical recording medium is arranged such that, at room temperature, the width of a stable magnetic domain of the reproducing layer is wider than the width of the recorded magnetic domain formed in the recording layer at the time when information has been recorded therein, and that, at temperature exceeding a predetermined value, the relationship between these widths is reversed. Accordingly, upon irradiation of a light beam, there is transferred and reproduced, to and from the reproducing layer, the magnetic domain of only that portion of the recording layer corresponding to the center portion of the light beam where the temperature of the reproducing layer exceeds the predetermined value.

Abstract: A magneto-optical recording medium of the present invention has a recording layer made of a perpendicular magnetization film, and a readout layer which is in an in-plane magnetization state at room temperature and changes into a perpendicular magnetization state with a rise in temperature. When the magneto-optical recording medium is irradiated with a light beam, the readout layer separates into three regions: a region in an in-plane magnetization state, a region in a perpendicular magnetization state, and a region having a temperature not lower than the Curie temperature thereof. Only the region in the perpendicular magnetization state allows copying of the magnetization of the recording layer. Therefore, even when the diameter and intervals of recording bits on the recording layer are very small, it is possible to reproduce a target recording bit separately from a recording bit adjacent to the target recording bit.

Abstract: A magneto-optical recording medium having a substrate whereupon a transparent dielectric layer, a readout layer showing in-plane magnetization at room temperature and perpendicular magnetization with an increase in temperature, a metal film layer, a recording layer made of a perpendicularly magnetized film, and a protective layer are formed in this order, wherein the film thickness of the readout layer is between 5 nm and 30 nm, the film thickness of the metal film layer is between 6 nm and 40 nm, and the film thickness of the recording layer is between 20 nm and 80 nm. Since recording domain information at a portion showing in-plane magnetization is masked, even when adjacent recording bit enters into the beam diameter of a light beam focused, it is possible to separately reproduce individual recording bits with high signal quality.

Abstract: In a magneto-optical recording medium including a reading-out layer, which is in an in-plane magnetization state at a room temperature and in a perpendicular magnetization state when the temperature rises, and a recording layer, which is in a perpendicular magnetization state at a room temperature to a Curie point, an intermediate layer having in-plane magnetization component and a lower Curie point than the recording medium is formed between the reading-out layer and the recording layer so as to abruptly change magnetization state of the reading-out layer. Since magnetization state of the reading-out layer is abruptly changed, recording is carried out highdensely. Moreover, since exchange-coupling between the reading-out layer and the recording layer is controlled, a recording characteristic is improved.

Abstract: A magneto-optical disk provided with a record layer having a recording magnetic domain where data are recorded, an auxiliary reproduction layer for transferring the record data in the record layer to a reproduction layer by generating a floating magnetic field corresponding to the data in the record layer, and the reproduction layer from which the data are read out through irradiation of a light beam, which are sequentially layered while interposing nonmagnetic intermediate layers therebetween. The stable magnetic domain width in the auxiliary reproduction layer is shorter than the recording magnetic domain width at room temperature and extends as the temperature rises and becomes longer at or above a first temperature. The stable magnetic domain width in the reproduction layer is longer than the recording magnetic domain width at room temperature and lessens as the temperature rises and becomes shorter at or above a second temperature which is lower than the first temperature.