Abstract: A magnetic field sensing element comprises an underlayer formed on a substrate, a giant magnetic resistance element formed on the underlayer for detecting a change in a magnetic field, and an integrated circuit formed on the substrate for carrying out predetermined arithmetic processing based on a change in a magnetic field detected by the giant magnetic resistance element, wherein the giant magnetic resistance element and the integrated circuit are formed on the same surface.

Abstract: This invention relates to a multi-layer magneto-optic recording medium having an information recording layer and an initializing layer that can be overwritten by light modulation, and in which adjacent layers, including auxiliary layers provided for more efficient transfer from the initializing layer to the recording layer, are coupled by an exchange force. This structure enables high-density, high-speed recording of audio information, visual information, and computer data.

Abstract: A multi-layer magneto-optic recording medium having an information recording layer and an initializing layer that can be overwritten by light modulation, and in which adjacent layers, including auxiliary layers provided for more efficient transfer from the initializing layer to the recording layer, are coupled by an exchange force. This structure enables high-density, high-speed recording of audio information, visual information, and computer data.

Abstract: A method of making a magneto-optical disk. A first AlGeN dielectric film is formed by reactive sputtering on a substrate. Two targets, one of aluminum and one of germanium, are used in the sputtering in a mixed atmosphere having at least nitrogen gas. Alternatively, a single target using an aluminum germanium alloy can be used. A magnetic film is formed on top of this dielectric film. A second dielectric film is then formed on top of the magnetic film. An adhesive film is formed on top of the second dielectric film and a second substrate adhered thereto.

Abstract: An optical disc comprises two facing disc units, at least one of which has a recording layer formed on its surface facing to the other disc unit. The disc units are bonded together by a layer of adhesive which may be a room-temperature curing thermosetting adhesive having a glass transition temperature higher than the upper limit of the range of temperatures of environments in which the disc may be used. Alternatively, the adhesive may be a room-temperature curing two-pack epoxy adhesive which comprises a bisphenol epoxy resin base agent and a modified aliphatic polyamine curing agent, and which has a viscosity of 100-1000 cps, a pot life of one hour or more, a cure shrinkage of 1.0% or less, a water absorption, after curing, of 0.2% or less, and a Shore hardness, after curing, of 80-90.

Abstract: This invention relates to a multi-layer magneto-optic recording medium having an information recording layer and an initializing layer that can be overwritten by light modulation, and in which adjacent layers, including auxiliary layers provided for more efficient transfer from the initializing layer to the recording layer, are coupled by an exchange force. This structure enables high-density, high-speed recording of audio information, visual information, and computer data.

Abstract: An optical disk adapted to resist moisture absorption, warping and static charge is disclosed. The disk includes an SiO.sub.2 film coating over at least a portion of a disk substrate. Additionally, an optical disk having a magnetic film protected by a fluorocarbon polymer is disclosed. Either of such disks can be used individually or, alternatively, they can be used in a laminated structure having two disks laminated in a face-to-face relationship. The laminated structure can be covered with SiO.sub.2 film.

Abstract: A magnetic thin film memory is provided including a plurality of magnetic thin film memory elements each adapted to record information on the basis of the direction of magnetization of a magnetic thin film thereof, the magnetic thin film memory elements being each composed of at least the magnetic thin film and a switching element. With such a constitution the magnetic thin film memory can be reduced in size while a sufficiently large signal can be obtained with a substantially improved SN ratio. A method for recording and reproduction information using the magnetic thin film memory is also provided. In another aspect, the present invention provides a magnetic thin film memory element including at least two kinds of magnetic layer, and a nonmagnetic layer which is interposed between the magnetic layers wherein the two kinds of magnetic layers are stacked so as to be coupled to each other by an exchange interaction through the nonmagnetic layer.

Abstract: A MR element which has a basically three-layered structure wherein the first and the second magnetic layer sandwich the nonmagnetic layer or of a basically five-layered structure wherein nonmagnetic layers are sandwiched between the first and second magnetic layers and between the second and third magnetic layers, respectively. The MR element of such arrangement offers a surprisingly large MR ratio under application of a sufficiently low magnetic field despite such a simple arrangement thereof.

Abstract: A magnetic thin film memory device having information recorded in a magnetic thin film thereof by the direction of magnetization, and adapted to reproduce the recorded information on the basis of the voltage generated as a result of the change of the magnetization direction due to the extraordinary Hall effect, magnetoresistance effect or the like.A magnetic thin film memory device in which a magnetic thin film is formed of ferrimagnetic substance having perpendicular magnetic anisotropy, and producing extraordinary Hall effect in the composition of RE rich and having the minimum saturation field which enables recording in a small magnetic field and is hard to be influenced by temperatures.

Abstract: A magnetic thin film memory wherein the memory is composed of magnetic thin films with a layer of a higher coercive force and a layer of a lower coercive force via a nonmagnetic layer laminated repetitively, or magnetic thin films having the easy magnetization axis which lies between the perpendicular and the horizontal directions of the magnetic thin film, and information is recorded on the layer of a lower coercive force, or information is recorded by changing the direction of the magnetization by means of a magnetic field applied by two recording lines which cross the magnetic thin film, thereby to obtain a sufficient amplitude of reproduction signal even when the size of the memory is reduced.

Abstract: An optical disc comprises two facing disc units, at least one of which has a recording layer formed on its surface facing to the other disc unit. The disc units are bonded together by a layer of adhesive which may be a room-temperature curing thermosetting adhesive having a glass transition temperature higher than the upper limit of the range of temperatures of environments in which the disc may be used. Alternatively, the adhesive may be a room-temperature curing two-pack epoxy adhesive which comprises a bisphenol epoxy resin base agent and a modified aliphatic polyamine curing agent, and which has a viscosity of 100-1000 cps, a pot life of one hour or more, a cure shrinkage of 1.0% or less, a water absorption, after curing, of 0.2% or less, and a Shore hardness, after curing, of 80-90.

Abstract: An optical disk having a warp preventive film for preventing the warp of the substrate which does not exfoliate for a long period by forming the warp preventive film on a textured area on the substrate surface with a minute embossment, and a method of manufacturing the optical disk by controlling the plasma etching condition for forming a textured area for reinforcing the bonding force of the warp preventive film on the substrate surface, so that the warp preventive film being bonded after forming the textured area may not exfoliate for a long period.

Abstract: A magneto-optical disk comprising a substrate, a dielectric film made of aluminum germanium nitride disposed on the substrate and a magnetic film disposed on the dielectric film. The magnetic-optical disk has increased Kerr rotational angle, while having excellent corrosion resistivity and high performance with respect to the CNR ratio.

Abstract: A megneto-optic recording medium which is comprised of a first, a second, a third and a fourth magnetic layers coupled each other between the adjacent layers by an exchange force, wherein said first through fourth magnetic layers satisfy T.sub.c1 <T.sub.c2, T.sub.c3 <T.sub.c2, T.sub.c1 <T.sub.c4 and T.sub.c3 <T.sub.

Abstract: This invention relates to a multi-layer magneto-optic recording medium having an information recording layer and an initializing layer that can be overwritten by light modulation, and in which adjacent layers, including auxiliary layers provided for more efficient transfer from the initializing layer to the recording layer, are coupled by an exchange force. This structure enables high-density, high-speed recording of audio information, visual information, and computer data.

Abstract: In a magneto-optical recording system for recording information with bits having upward magnetization and having downward magnetization on a recording layer of a magneto-optical recording medium, having four magnetic layers exchange-coupled with each other. A laser beam directed onto the medium is modulated to heat the magneto-optical recording medium to two values, for "High" writing and for "Low" writing. During "High" writing, the first to third layers lose magnetization because their Curie temperatures are exceeded, and the direction of the magnetization of the first layer, which is the recording layer is determined mainly by the magnetostatic coupling from the the fourth layer. During "Low" writing, the first and the third layers lose their magnetization as their Curie temperatures are exceeded, and the direction of the magnetization of the first layer is determined by the exchange coupling from the second layer, which in turn is dependent on the exchange coupling from the fourth layer.