Abstract: A method and device of head positioning in an information recording/reading device in which a magnetic recording medium with data tracks for recording information thereon is provided and a magnetic head is positioned on the data track to record/read out the information, wherein a data signal is recorded in the data recording layer of said recording medium, a servo signal is recorded in the servo signal recording layer located below said data signal recording layer, said data signal is read out using a data magnetic head whereas said servo signal is read out using a servo magnetic head, and the frequency of said servo signal is within the range of the gap-null frequency of said data magnetic head whereas the frequency of said data signal is within the range of the gap-null frequency of said servo magnetic head, and said magnetic head is positioned on the data track on the basis of said servo signal.

Abstract: A magnetic recording medium is constructed with a substrate made of glass, one or two underlayers, and a magnetic film. In order that the easy magnetization axis of the magnetic film is parallel to the magnetic film, an underlayer having an NaCl crystallographic structure is superposed on the substrate. A magnetic film made of a Co based alloy having a hexagonal close packed crystallographic structure is formed on this underlayer, putting an underlayer made of a material having a body centered cubic crystallographic structure therebetween at need. Magnetic anisotropy of the magnetic film is increased by forming grooves in a predetermined direction in a surface portion of the substrate. These grooves play a role also for defining the orientation of the underlayer made of the material having an NaCl crystallographic structure.

Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magneto-resistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Abstract: A magnetic recording medium comprising a substrate, a diffusion element layer formed on the substrate from a material to be diffused into a magnetic film by heating, a diffusion barrier formed in a desired pattern on the diffusion barrier, and the magnetic film formed on the pattern of the diffusion barrier and on other area than the area of the pattern, the magnetic film having a portion of reduced saturation magnetization in repetition in a direction perpendicular to a recording direction. The magnetic recording medium can be obtained by forming a diffusion element layer, a diffusion barrier in a desired pattern, and a magnetic film, in a stacked form on a substrate, followed by heating.

Abstract: By using an information recording medium comprising at least a substrate and an information recording film which is mounted on the above substrate and changes the physical property under irradiation of a recording energy beam, wherein the surface of the information recording area of the above substrate is uneven, both surfaces of the above recording film are also uneven, and an inorganic protective layer is provided in contact with the surface of the above recording film opposite to the above substrate, fine recording points can be formed stably without complicated control of the recording power and recording waveform so that an optical disk unit can record data simply in high density.

Abstract: A magnetic recording data storage system includes a magnetic recording medium having pits formed therein, the pits defining recording tracks on the magnetic recording medium and being arranged in a staggered manner relative to respective center lines of the recording tracks, a magnetic head including an inductive element for recording data on the recording tracks and a magnetoresistive element for reproducing data from the recording tracks, one of (1) a unit for magnetically producing a signal from the pits, and (2) an optical unit for optically producing a signal from the pits, the optical unit including a laser for illuminating the pits, servo means for positioning the head on the recording tracks based on the signal produced from the pits, the servo means including a dual-stage actuator including a rough movement portion and a fine movement portion.

Abstract: A ferromagnetic thin film of manganese and aluminum having varied atomic concentrations of manganese and aluminum in the direction perpendicular to the film plane, preferably the Mn atomic concentration being preferably in a range of 45 to 65% by atom, has a spontaneous magnetization equivalent to that of the bulk of manganese-aluminum alloy and also a high magnetic anisotropy.In addition, a magnetic recording medium comprises a substrate and a magnetic film formed on the substrate, the magnetic film being a thin film in a stacked structure of thin layers of manganese and thin layers of aluminum, laid open upon one another alternatingly in the film thickness direction.Finally, a manganese-silicon magnetic multi-layer film comprises thin layers of manganese and thin layers of silicon laid upon one another alternatingly.

Abstract: A high-density magnetic recording and optical reproducing apparatus for magneto-optically reproducing information magnetically recorded on information tracks on a recording medium, the apparatus comprising two laser beam sources emitting laser beams having different wavelengths respectively, an optical system for directing the laser beams from the two laser beam sources toward and onto the recording medium so as to irradiate the recording medium with laser beam spots partly overlapping each other, two photo detectors detecting the laser beams reflected from the surface of the recording medium, and a differential amplifier detecting the difference between the output signals of the two photo detectors thereby generating the differential signal as a reproduced output.

Abstract: A weak-link Josephson junction is of the type employing a thin film of an oxide superconductor, in which a crystal grain boundary produced reflecting an artificial crystal defect is utilized as the weak-link junction. The crystal grain boundary is formed concretely by a method in which atoms of different species are deposited on the predetermined part of the surface of a substrate, the predetermined part of the surface of a substrate is disturbed, or parts of different crystal face orientations are formed at the surface of a substrate, whereupon the superconducting thin film is epitaxially grown on the substrate, or by a method in which the predetermined part of the superconducting thin film, epitaxially grown on a substrate, is diffused with atoms of different species hampering a superconductivity, or the predetermined part of the superconducting thin film is disturbed, whereupon the superconducting thin film is annealed.

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 think 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.

Abstract: A magnetic recording medium comprises a non-magnetic substrate and a perpendicular magnetic film of Co-based alloy having a large perpendicular magnetic anisotropy having 0.001 to 5% by atom of nitrogen formed directly or through an underlayer on the non-magnetic substrate. A more preferable range of the nitrogen content is 0.01 to 1% by atom.

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.

Abstract: A magnetic recording medium which comprises a non-magnetic substrate, a magnetic film formed on the substrate and a protective film provided on the magnetic film, the protective film being composed of at least two groups of element, the element in one group being at least one of B and C having a smaller atomic size, and a concentration of the element increasing from the interface side of the protective film with the magnetic film toward the opposite face side throughout the protective film has an improved durability against a magnetic head.

Abstract: A perpendicular magnetic recording medium according to this invention comprises an electrically conductive underlayer formed on a non-magnetic substrate, in the case where no high permeability magnetic film is deposited, and a magnetic thin film having a perpendicular magnetic anisotrophy is formed thereon. In the case of a so-called double-layer structure including a high permeablilty magnetic film, on the non-magnetic substrate are formed the high permeablilty magnetic film, an intermediate film, and a magnetic thin film one on another in this order. The nearest neighbor's distance of atoms of the underlayer and the intermediate film is not smaller than 0.25 nm (2.5 .ANG.) and not greater than 0.32 nm (3.2 .ANG.) and they are made of at least one selected from the group consisting of V, Ru, Zn, Os, Rh, Ir, Mo, W, Re, Pd, Pt, Nb, Ta, Sn, Al, Au, Ag, Ti, nitrides and oxides of these elements.

Abstract: Disclosed is a magnetic recording medium comprising a predetermined substrate having or not having a soft magnetic thin film provided thereon, a layer formed thereon for controlling the columnar crystal grain size in a thin magnetic film formed on the substrate, and the thin magnetic film provided on the columnar crystal grain size control layer. The above-mentioned columnar crystal grain size control layer is a film having a close-packed hexagonal lattice structure and made of one element selected from among Ru, Sc, Y, and Zn, or two or more elements selected from among Ru, Sc, Y, Zn, and Ti; or a film having a close-packed hexagonal lattice structure and made of Co or a Co-based alloy. The columnar crystal grain size control layer may consist of two layers, the under layer of which is made of one or more elements selected from among Si, Ge, and Sn.

Abstract: Disclosed is a perpendicular magnetic recording medium wherein an underlayer made of a material containing Si and/or Ge as its principal ingredient is deposited on a substrate, and a perpendicular magnetic film made of a Co-based alloy is deposited on the underlayer. With the perpendicular magnetic recording medium, the perpendicular magnetic film has an enhanced degree of C-axis orientation, and the bond strength between the perpendicular magnetic film and the substrate is also enhanced when the substrate is non-metallic.

Abstract: An ion beam source characterized in that a needle-like tip is comprised of a carbide, a nitride, or a diboride of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb and Ta, a hexaboride of at least one element of rare earth metal elements of atomic numbers 57-70, or carbon. Stable ion beam emission of high brightness and long life can be obtained by using the needle-like tip of the said material.

Abstract: A source of charged particles beam which can be used either as an electron source or an ion source and has a tip formed of carbide, nitride or di-boride of at least one of elements Ti, Zr, Hf, V, Nb and Ta or formed of hexa-boride of at least one of rare earth metal elements of atomic number 57 to 70.

Abstract: A cathode for an electron source according to this invention comprises an emitter tip made of an electron emissive material, a filament for holding the emitter tip, and a binder for binding the emitter tip and the filament, the filament and the binder being made of glassy carbon. The binder can have a carbide or boride powder incorporated therein. The cathode according to this invention can be produced by using a thermosetting resin of predetermined shape as the starting material of the filament, fixing the emitter tip to a predetermined position of the thermosetting resin with the adhesive agent made of the raw thermosetting resin, and heating the resultant assembly in a non-oxidizing atmosphere to carbonize the resinous portions. This cathode is structurally very simple. Moreover, the adhesion between the filament and the emitter tip is excellent, and the emitter tip can be heated to high temperatures above 2,000.degree. C. by causing current to flow through the cathode.