Abstract: A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged, and that of the reference layer is aligned either upward or downward; radiating a laser beam onto the medium; pulse modulating an intensity of the laser beam in accordance with binary data to be recorded; when the laser beam is radiated, applying a bias field to the irradiated portion; and when the intensity of the pulse-modulated laser beam is at high level, forming one of the bit having upward-magnetizatio

Abstract: A data storage system is described which includes a magnetostrictive, anisotropic, ferromagnetic film whose domains exhibit a preferred orientation and are initially poled in one direction along the preferred orientation. A field is applied in opposition to the one direction, the field being insufficient to cause a switching of the poled domains. An electrostrictive film is placed in contact with the ferromagnetic film and a writing system is provided to actuate the electrostrictive film to impart stresses to the ferromagnetic film at selected locations. The induced stresses reduce the anisotropy energy of the ferromagnetic film at the selected locations and enable the domains thereat to become poled in accordance with the applied field. In one version of the invention, the writing means comprises a directed energy beam such as a laser or electron beam. In another version, the writing system employs surface acoustic waves in combination with a scanned energy beam.

Abstract: A method of this invention is a non-overwritable method of recording information on a magnetooptical recording medium in which at least two layers including a first layer comprising a magnetic thin film having a perpendicular magnetic anisotropy, and a second layer comprising a magnetic thin film having a perpendicular magnetic anisotropy, and having a Curie temperature higher than or almost equal to a Curie temperature of the first layer are stacked to be exchange-coupled to each other, and a direction of magnetization of only the second layer can be aligned in a predetermined direction by a first external field at a room temperature while a direction of magnetization of the first layer is left unchanged. The medium which has already been set in a state wherein the direction of magnetization of the second layer is aligned in the predetermined direction, and a interface magnetic wall is formed between the first and second layers is prepared. A beam is radiated on the prepared medium while rotating the medium.

Abstract: A method and apparatus for recovering information prerecorded in a vertically magnetized magneto-optic recording element wherein a laser is operated in a state of polarization instability (i.e., its TE and TM losses are equal). The linearly polarized (TE and TM) output of the laser is converted to circularly polarized (left-handed and right-handed) polarized radiation, and the latter is used to scan irradiate the recording element. Upon being reflected by the recording element, the circularly polarized radiation is reconverted to linear polarization and fed back to the laser cavity. Depending on which polarization mode (TE or TM) experiences the lesser loss as a result of the MCD effect, the laser operates in either its TE or TM mode. Means are provided for detecting the instantaneous polarization mode of the laser which, in turn, is indicative of the orientation (up/down) of the magnetic domains scanned by the laser radiation.

Abstract: In a magneto-optical eraser, information recorded on a magnetic layer of a magneto-optical recording medium is erased or initialized by applying light over the magneto-optical recording medium from a light source (13,43) in a reflector to heat the magneto-optical recording medium and also by supplying a magnetic field to the magneto-optical recording medium along its axis of easy magnetization. In one form, a plurality of light sources (13) may be disposed in the surface of a single reflector (12). Alternatively, the magneto-optical recording medium may be double-faced, and a light source and reflector may be disposed on each side of the double-face recording medium. A pre-heater (52) may increase the temperature within a glass housing (50,51) to a temperature less than the softening point of the medium substrate.

Abstract: A recording method for a magneto-optic memory medium of exchange-coupled type having a recording layer of a low Curie point and high coercive force and a reading layer of a high Curie point and low coercive force, which comprises the steps of: applying a magnetic field to the magneto-optic memory medium to develop a predetermined data in the reading layer, and then applying both an optical beam and a magnetic field to the magneto-optic memory medium for writing the predetermined data in the recording layer, and simultaneously verifying the data upon the writing on the basis of a Kerr effect of the optical beam caused by the reading layer.

Abstract: An information recording method, which performs recording of an information by use of an optical magnetic recording medium provided with a first magnetic layer and a second magnetic layer having higher Curie point and lower coercive force at room temperature than the first magnetic layer, by carrying out initialization to align the magnetization direction of the second magnetic layer in one direction and then irradiating an optical beam of which power has received modulation between the two values which are not zero depending on the information, thereby recording the information as the arrangement of a magnetic domain on the above medium, has characteristic such that, when initialized again after recording of the above information, an interface magnetic wall is permitted to exist between said first and second magnetic layers at the portion other than said magnetic domain.

Abstract: A Curie temperature (Tc) writing magnetooptical recording medium which uses a dual perpendicular magnetic layer is composed of a first layer having a low Curie point (TL) and a high coercive force (HH) and a second layer having a relatively high Curie point (TH) and low coercive force (HL) and wherein data is written by applying an external magnetic field to the medium which is heated to a temperature higher than the low Curie point (TL) and lower than the high Curie point (TH). The Tc writing magnetooptical recording medium is characterized in that both the first and second layers are made of an RE-Fe-Co amorphous alloy, wherein the RE represents at least one rare earth metal selected from the group consisting of Tb, Dy, Gd and Ho.

Abstract: First and second beam splitters are arranged on the optical path of a light beam emerging from a recording surface, and such that the phases and amplitudes of the respective polarized light components of a light beam incident thereon are changed to equal extends. As a result of this arrangement, the state of polarization beam of the light beam emerging from the recording surface is maintained when a light beam is outputted through the two beam splitters. Stable reproduction signals and servo control signals for focusing, tracking, and the like can be reliably supplied by utilizing an apparatus of this invention.

Abstract: A magneto-optic method and apparatus for recording digital data employs selective heating beyond the Curie or compensation temperature T.sub.c of the record material in the presence of an external magnetic field for recording information by rotating the direction of magnetization at the affected record locations, and the selective detection of the state of rotation of the polarization direction at information storage locations in a recording medium by way of analyzing the state of rotation of the light transmitted through said record material. The writing and retrieval of information are performed by means of a sharply pointed tip placed at an essentially constant distance above the recording medium, the sharpness of the apex of said tip determining the resolution and the achievable storage density. The heating of the storage locations is accomplished by means of a laser beam directed onto the recording medium through said slidably arranged tip.

Abstract: A magneto-optical data reading member includes a transparent disk substrate, and land-shaped areas formed on the disk substrate in a spiral manner so as to be parallel with each other, and groove-shaped areas formed to be stepped with respect to the land-shaped areas, wherein each of the land-shaped and groove-shaped areas has, in a surface region thereof, a first magnetic film for reading data having a predetermined Curie temperature and a predetermined magnetic coercive force, and a second magnetic film for reading data, formed on the first magnetic film, having a Curie temperature higher than the predetermined Curie temperature and a magnetic coercive force higher than the predetermined magnetic coercive force, and having a plurality of memory pits in series according to the information data to be recorded.

Abstract: This invention relates to a magnetooptical recording medium that is capable of direct overwriting by light intensity modulation without using a separate source for generating an external magnetic field and that has four magnetic layers superposed on a substrate, wherein said magnetic layers has vertical magnetic anisotropy and any two adjacent layers being bound by exchange force. The medium is characterized in that a fifth magnetic layer not bound by exchange force is provided over the fourth magnetic layer or that a layer made of a rare earth element/transition metal alloy in which the magnetization of rare earth elements is dominant is provided between the first and second magnetic layers which are bound together by exchange force.

Abstract: A magneto-optical reproducing device in which a reflected light signal from a magneto-optical disk is divided by an astigmatic analyzer. The analyzer both divides the light signal according to linear polarization, for data signal detection, but also introduces astigmatism in one of the divided beams to allow focus detection.

Abstract: A known film becomes transparent when heated from a first temperature (for example, room temperature) to a second temperature and non-transparent when heated to a third temperature. These changes are reversible. A film of this type is to be used as a record carrier for optical information. The film (A) is passed continuously or stepwise past an erasing device (L), a cooling device (K), a preheating device (V) and a writing device (S). The film (A) can be made either transparent or non-transparent by heating it to different predetermined temperatures. The information can be recorded on the film in either its transparent form in non-transparent surroundings or in its non-transparent form in transparent surroundings. The device can be used together with the film to obtain a "paperless" office, because the recordings can be erased from the films, which can therefore be constantly re-used.

Abstract: An apparatus and method for directly overwriting data on a magnetooptic data storage medium. The apparatus includes a magnet (16) disposed adjacent to a recording medium (14) which provides a static magnetic field which interacts with the medium (14). The interaction is broadbased, having an area including multiple tracks (17) of the medium that encompass up to an entire data band. A first laser focuses a continuous laser beam (22) onto a track (17) of the recording medium within the location of the reversed magnetic field (18). This first laser beam (22) provides for erasure of the medium. A second laser focuses a pulsed laser beam (26) onto the erased track (17) within the location of the nonreversed magnetic field (20). This pulsed laser beam (26) provides for writing to the medium.

Abstract: A three-dimensional combined magneto-optic memory and logic processor consisting of layers of magnetic bubble material spaced from and parallel to one another. Each layer has a pattern of magnetic bubbles formed under the control of an external data processing system. A laser beam is directed through the layers, and binary signals corresponding to the overall patterns of the magnetic bubbles on all the layers which intersect the beam are detected by a first detector array. Data and logic functions are programmed on to each layer by appropriate control of the magnetic bubbles by the external processing system. Wave guides are provided to reflect light from the magnetic bubbles to a second detector array. In this manner, the two detector arrays may be caused to generate electric signals representing data and logic functions, thereby eliminating the bottle-neck between processor and memory which is prevalent in prior art data processing systems.

Abstract: An optical storage device having a mass storage medium which remains stationary as data is transferred by a laser. The stationary mass storage medium permits rapid data transfer since delay due to rotation of the medium, as in a compact disk, is eliminated.

Abstract: Methods for directly over-writing the binary data value of a bit of digital data, stored in a particular one of a multiplicity of microscopic storage regions of a thin-film magneto-optic recording layer, in the absence of a substantial externally applied bias magnetic field, employ a magnetic material having a compensation temperature a few tens of degrees centigrade above room temperature. A source of energy is energized to heat the particular storage region to a sufficiently high temperature that the self-demagnetization field of the recording layer material inverts the net magnetic moment of that region. Multiple over-writing of the long-term stable stored data values can be provided.

Abstract: A magneto-optic playback apparatus which plays back information from a recording layer (RL) which exhibits different light absorption of left and right circular polarized beams emitted from a laser (L). The laser (L) operates in two different polarization modes, DE and TM. Polarization converter (PC) converts linear polarized radiation from the laser in one plane to one circular polarization orientation (left or right) in one direction of transmission, and then converts the opposite circular polarized radiation orientation back to linear polarization in the other direction of transmission. The laser switches between modes according to the magnetic orientation of the medium which is determined by the reflected light. Loss control element (LC) selectively increases the TE losses in the extended laser cavity. The self-coupling laser's operation in either the TE or TM mode depends on the differential absorption by the media of right (RCP) or left (LCP) handed circularly polarized beams.

Abstract: A magneto-optical recording medium including a recording layer and a bias layer being stacked one upon the other to apply coupling interaction which is mainly magnetostatic interaction to each other, the bias layer having a magnetization-reversing temperature higher than that of the recording layer. The medium is irradiated with laser beam pulses having a recording level and an erasing level lower than the recording level, thereby recording and erasing the information. When the medium is irradiated with the laser beam pulse having the recording level and the irradiated region is cooled to the magnetization reversing temperature T.sub.rR, the magnetization of the beam-irradiated region of the recording layer is aligned with a direction of the leakage magnetic field leaking from the recording layer. When the medium is irradiated with the laser beam pulse having the erase level and the irradiated region is cooled to T.sub.

Abstract: A magneto-optical data recording system includes magnetic field pulse applying apparatus for applying to a magneto-optic recording medium a magnetic field pulse of a polarity corresponding to code data to be recorded, and a heating apparatus for heating the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to be recorded. During recording, the magnetic field pulse applying apparatus applies a magnetic field pulse of a polarity corresponding to code data along a track of the recording medium and the heating apparatus continuously heats the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data to thereby directly overwrite the code data. The magnetic field pulse applying apparatus includes a magnetic coil driven by code data from a source of code data (data generator).

Abstract: A high density magnetooptical recording and playback method is disclosed. The magnetooptical recording medium comprises a recording hold magnetic layer and a playback magnetic layer magnetically coupled with each other. Prior to the playback operation, the playback magnetic layer is initialized by an external magnetic field. A laser light is irradiated to locally heat the medium and cause transfer of magnetization in the recording hold magnetic layer to the playback magnetic layer. The signal is read out by the interaction of the laser light and the transferred magnetization.

Abstract: A magneto optic recording medium comprising a substrate, an amorphous magnetizable rare earth-transition metal alloy layer, a transparent dielectric layer on at least one side of the magnetizable layer, and a reflective surface located to reflect light through the magnetizable alloy layer. The dielectric layer is comprised of silicon carbide of the formula SiC.sub.x, wherein x, the molar ratio of carbon to silicon, is greater than 1. The dielectric layer is preferably deposited by direct current magnetron sputtering at low argon partial pressure from an electrically conductive mixture of silicon carbide and carbon. The medium exhibits similar or improved characteristics over media constructed with present dielectrics, for example, silicon suboxide (SiO.sub.y, y<2).

Abstract: A system for reading and writing binary information onto at least one optical recording surface of a magneto-optical disk includes a hydrodynamic bearing for traveling above the optical recording surface of the magneto-optical disk, an objective lens carried by the hydrodynamic bearing for focusing laser light to heat selected areas on the optical recording surface, and a magnetic writing head also carried by the hydrodynamic bearing for recording selected magnetic orientations, representing binary states, onto the heated areas on the magneto-optical memory disk.

Abstract: An optomagnetic disk apparatus includes a holder for holding a cartridge which stores an optomagnetic disk therein and which is moved while a cartridge having an openable shutter is held therein. Shutter openers for opening/closing the shutter are movably arranged on the holder. A wire is looped between the shutter openers. Ends of the wire are fixed to the frame. When the holder is moved, the wire is pulled, and the shutter openers are selectively moved to open/close the shutter. The optomagnetic disk apparatus also includes a magnet unit for applying an external magnetic field to the optomagnetic disk when information is erased from or written in the optomagnetic disk. The magnet unit has a flat sectional shape and is rotatable.

Abstract: A magneto-optical recording medium including a first magnetic layer (having film thickness t1 and saturation magnetization Ms1) and a second magnetic layer (having film thickness t2 and saturation magnetization Ms2) which are respectively made from a rare earth-transition metal alloy and sequentially laminated on a substrate to jointly make up a recording layer. Only the first magnetic layer or both the first and second magnetic layers contain a light rare earth element. At room temperature, a transition-metal sub-lattice magnetic moment is dominant in the first magnetic layer, whereas a rare earth sub-lattice magnetic moment is dominant in the second magnetic layer, respectively. Substantially, the directions to stabilize magnetization of the first and second magnetic layers are inverse from each other and the expression shown below is satisfied.t1.times.Ms 1-t2.times.Ms2.ltoreq.5 (.mu.m.times.emu/cm.sup.

Abstract: A magneto-optical storage medium and overwrite system comprises a first magnetic layer (reading/writing layer) (3), a second magnetic layer (auxiliary layer) (5) and a third magnetic layer (initializing layer) (7), each of which is a rare earth-transition metal alloy, and interface layers (4,6) for isolating magnetic exchange interaction between the magnetic layers, respectively. The second magnetic layer is initialized by the magnetization of the third magnetic layer (7) at room temperature. The first magnetic layer and/or the second magnetic layer is heated by a laser beam (P1) for demagnetization and remagnetization. The demagnetized portion of the second magnetic layer is remagnetized to the opposite direction by the demagnetizing field from the periphery. The demagnetized portion of the first magnetic layer is remagnetized to the same direction of the second magnetic layer.

Abstract: A photomagnetic memory medium of an amorphous thin film of a rare-earth transition metal alloy of non-columnar structure deposited on a substrate. In order to achieve the non-columnar structure, the alloy is sputtered in the presence of a plasma but the plasma is confined by a magnetic field so as not to touch the substrate. The alloy is preferably TbFeCo.

Abstract: A magnetooptical recording medium provided with a first magnetic layer and a second magnetic layer having a higher Curie point and a lower coercive force than the first magnetic layer and being exchange coupled with the first magnetic layer satisfies the relation: ##EQU1## wherein H.sub.H is the coercive force of the first magnetic layer; H.sub.L is the coercive force of the second magnetic layer; M.sub.2 is the saturation magnetization of the second magnetic layer; h is the thickness thereof; and .sigma..sub.w is the magnetic wall energy between the first and second magnetic layers and a method of recording information on the same.

Abstract: A solid state memory device has a thin film for bubble memory, a laser light source, and optical means using a laser light emitted from the laser light source to cause information to be stored in the form of bubbles on the thin film for bubble memory and reproduce the stored information.

Abstract: An over write capable magnetooptical recording medium comprises a substrate and magnetic layers including first and second layers each having a perpendicular magnetic anisotropy. In the medium, a product of a saturated magnetic moment and a coercivity of the first layer is larger than that of the second layer, and non-magnetic element is doped in the first layer.

Abstract: An optical modulator utilizing a magnetic semiconductor device, whose operation is based on the Hall effect, includes a magnetic material formed on a semiconductor substrate. When an incoming beam of light having a dominant polarization direction is directed onto the magnetic material it becomes modulated. The result is an outgoing beam of light which has a rotated plane of polarization when compared to the dominant polarization direction. The direction of the rotated plane of polarization is indicative of the information stored in the magnetic material. The modulator of the present invention further includes a means for writing the information to the magnetic material and a semiconductor sensor means for electrically verifying the contents of the magnetic material.

Abstract: A method of magneto-optically recording and erasing information which comprises irradiating pulse-like laser beam onto a magneto-optical information storage medium including recording and bias layers which has perpendicular magnetic anisotropy and which are stacked one upon the other to apply coupling interaction which is mainly magnetostatic interaction to each other, and magnetization-reversing temperature of the bias layer being higher than that of the recording layer. When the recording laser beam is irradiated onto the medium, the beam-irradiated portion of the medium is heated to form a reversed magnetic domain in the bias layer, magnetization of the recording layer is reversed by first leakage magnetic field applied to the recording layer when beam-irradiated portion is then cooled, and magnetization of the bias layer is directed in same direction as that under initial state by second leakage magnetic field, applied to the bias layer.

Abstract: A magnetic thin film recording layer comprised primarily of a light rare earth element and a transition metal element is disclosed. Other elements are optionally included in the film. The film has an easy axis of magnetization perpendicular with respect to the surface of the film. Magneto-optic recording systems using such films are also disclosed.

Abstract: A magneto-optic memory medium of an exchange-coupled ferrimagnetic double-layered structure having a recording film of a specific amorphous GdTbFe alloy and a reading film of a specific amorphous GdNdFe alloy.

Abstract: A method and an apparatus for MO recording that allow real overwrite by light power modulation with a combination of a storage medium consisting of a single-layer RE-TM film and a single-laser source. The medium has a Curie temperature not less than about 500.degree. C. and has high saturation magnetization around 200.degree. C. The coercive force drops to a level that allows the magnetization to be reversed by the demagnetization field at around 200.degree. C.

Abstract: A recording apparatus for recording data on a magnetooptical disk includes a rotating device for rotating the magnetooptical disk, a laser device for irradiating the magnetooptical disk, a controller for controlling the intensity of the laser beam, an initial field applying device for initializing the magnetooptical disk, and a bias field applying device for applying a bias field to an area of the magnetooptical disk. The laser device, the controller, and the field applying devices are positioned at the same side of the magnetooptical disk as the rotating device to reduce the height of the apparatus.

Abstract: A multilayer, direct-overwrite, magnetooptic recording element comprises first and second layers of magnetic materials having different magnetic coercivities and Curie temperatures. According to the invention, one of the two magnetic layers is doped with zirconium. The addition of zirconium has the effect of substantially lowering the Curie temperature of the doped layer, thereby enlarging the Curie temperature differential between the magnetic layers. The zirconium additive also has the effect of stabilizing the magnetic properties of the doped layer.

Abstract: An overwritable magneto-optic recording system has a recording medium with a substrate, a recording magnetic film and a reproducing magnetic film deposited on the substrate. The reproducing magnetic film has a Curie temperature lower than that of the recording magnetic film, and coercive force Hc higher than that of the recording magnetic film. In a write process, a magnetic head writes data magnetically on the recording magnetic film, then, in a transfer process, an optical head (which is positioned downstream along the relative movement of the recording medium and the optical head) heats the recording medium higher than the Curie temperature of the reproducing magnetic film so that the reproducing magnetic film loses its magnetic property. During the cooling period after heating, recorded bits in the recording magnetic film are transferred to the reproducing magnetic film which restores its magnetic property.

Abstract: Optical shutters having a magneto-optical material confined in a holding plate which allows a light to pass through the magneto-optical material. When the intensity of a magnetic field applied to the magneto-optical material is changed, an amount of a polarized light passing through the magneto-optical material is adjusted. A magnetic head with a coil has open ends which are disposed to face the outer surface of a shutter member. A plurality of such optical shutters are arranged to form an optical shutter array.

Abstract: A magnetooptic disk has circumferentially-spaced-apart, radially-aligned embossed sector areas which indicate data storage tracks. The sector areas include embossed signals which indicate track-following information, and in a second area which trails the track-following information, track-seeking information is carried by the embossed signals. A magnetooptic coating covers the entire disk including the embossed sector areas. Readback clock synchronization signals are recorded over the track-seeking area to enable synchronizing a readback phase-locked loop such that more of the areas between sector areas can be used for recording data signals. During track seeking, the track seek controlling embossed signals are read using intensity demodulation, while in track following, during a readback, the clock signals recorded over the embossing are read for synchronizing the readback circuits. During recording, the synchronization signals are recorded over the embossed area dedicated to track seeking.

Abstract: A method of reproducing a signal from a magneto-optical recording medium is disclosed in which the medium is formed of a first magnetic film, a second magnetic film and a third magnetic film which are magnetically coupled to one another at room temperature T.sub.RT, wherein the Curie points Tc1, Tc2 and Tc3 of the first, second and third magnetic films are in the relationship of Tc2>T.sub.RT Tc2<Tc1, and Tc2<Tc3, and the coercive force Hc1 of the first magnetic film is small in the vicinity of the Curie point Tc2 of the second magnetic film, and the coercive form Hc3 of the third magnetic film is larger than a minimum required magnetic field intensity within a temperature range between the room temperature TRT and a predetermined temperature T.sub.PB which is higher than the Curie point Tc2 of the second magnetic film. A signal is reproduced from the magneto-optical recording medium by heating it to the predetermined temperature T.sub.

Abstract: A magnetic storage medium is read by incident polarized light and reflected outgoing light defining a common plane. The polarized incident light preferably has a polarization vector at 40.degree. to 50.degree. to this plane and at the storage medium, the magnetization is in a direction perpendicular to the plane. The preamplified output signal V.sub.M from the photodiode transducing the outgoing light beam has a fixed value V.sub.O subtracted therefrom where V.sub.O is a function of the sensitivity and resolving power of the electronic circuitry. The signal V.sub.M -V.sub.O is then amplified and processed to represent the stored data.

Abstract: A magneto-optic information-carrying medium comprises three magnetic layers. A magnetic bias field is generated by a third layer which is premagnetized in the direction parallel to the thickness thereof.

Abstract: An apparatus for reading out information written on a magneto-optical data storage medium through magnetization thereof in one of opposite directions normal to a surface of the medium, comprising a device for emitting circularly or linearly polarized light to the storage medium in a direction parallel to the direction of magnetization of the storage medium, and a device for readng out the information based on a change in total quantity of the polarized light which is reflected from the storage medium or transmitted through the medium. The apparatus may comprise at least one polarizing beam splitter and a quarter-wave retardation plate. The device for reading out the information may comprise at least one data-reading optical detector which generates a signal corresponding to the detected total quantity of the light reflected from the storage medium.

Abstract: A magneto-optical information reproducing apparatus includes a device for applying a light beam polarized in a predetermined direction to a recording medium on which information is magnetically recorded, a first divider for dividing the reflected or transmitted light beam from the medium modulated into a polarized state in conformity with the information by magneto-optical effect into two light beams polarized in directions orthogonal to each other, the first divider being disposed so that the directions of polarization of the divided two light beams form an angle of 45.degree. with respect to the predetermined direction of polarization of the applied light beam, and a detector for detecting the divided two light beams.

Abstract: Disclosed is a magneto-optical recording element comprising a dielectric layer and an amorphous perpendicular magnetization film on a substrate, wherein the perpendicular magnetization film is a perpendicular magnetization film comprising at least Gd element as the rare earth metal element and Fe metal as the transition metal component, in which the Fe sub-lattice moments are dominant, the dielectric layer is a dielectric layer composed of amorphous silicon nitride, the magnetization Ms of the perpendicular magnetization film is set within a range represented by the following formula (1):20 emu/cc.ltoreq.Ms.ltoreq.70 emu/cc (1)and the product of the magnetization Ms and the coercive force Hc is set within a range represented by the following formula (2):100 emu.multidot.KOe/cc.ltoreq.Ms.multidot.Hc.ltoreq.500 emu.multidot.

Abstract: A spatial light modulation technique for a coherent optical processor, permitting binary spatial light modulators to represent a range of grey levels. The technique modulates a coherent input beam at a plurality of spatially separate image pixels, to produce a modulated beam having the image pixels spatially encoded thereon. The input beam is divided into N sub-beams, each of which is passed through a separate binary spatial light modulator to produce a modulated sub-beam. Each binary spatial light modulator comprises an array of sub-pixels, each of which either blocks or passes a portion of the sub-beam. One sub-pixel of each binary modulator corresponds to each image pixel. The modulated sub-beams are then combined. Weighting means are provided for modifying the intensity of light following the sub-beam paths by selected weighting values. The weighting values form a series in which each of N-1 weighting values differs from the preceding weighting value by a factor of 4.

Abstract: An associative data processor including a spin glass type amorphous magnetic film has input areas, output areas, and "hidden" or associative areas. A coil provides selective magnetic biasing, and lasers provide selective digital input to the input and output areas, which are intercoupled by the associative areas. Following input of a number of digital patterns to the processor, and "learning" by heating the associative areas, an incomplete input pattern may be applied, and the complete pattern read by sensing the polarization of reflected polarized light from the output areas.

Abstract: A magnetic recording medium comprising a substrate, a ferromagnetic thin film formed on the substrate, and a protective film formed directly on the ferromagnetic thin film, and a process for producing such magnetic recording medium. The expression "formed directly" refers to the technique for forming the protective film on the ferromagnetic thin film so that the interface therebetween is free from contamination by, for instance, conducting the protective film formation under the vacuum used when forming the ferromagnetic thin film.