Abstract: The invention provides a method of fabricating an optical recording medium comprising a phase change type recording layer containing at least one element selected from In, Ag, Te and Sb. The recording layer is formed by a sputtering technique wherein sputtering is carried out while an inert gas and an oxygen gas are introduced in a vacuum chamber in a sputtering system, so that the number of overwritable cycles can be increased by simple means.

Abstract: A phase change type optical recording medium of Ge--Sb--Te system wherein number of overwritable operation has been increased is provided. The optical recording medium has a substrate and a recording layer of phase change type on the substrate, and the recording layer contains Ge, Sb and Te as its main elements, and at least one of Ag and Au in total content of 0.2 to less than 2.5 at % (excluding 2.5 at %).

Abstract: An optical recording medium of phase change type which exhibits an increased number of overwritable operations is provided. The optical recording medium comprises a substrate, and a first dielectric layer, a recording layer, a second dielectric layer, and a metal reflective layer disposed on the substrate in this order, and the first dielectric layer comprises a dielectric layer 1a on the side of the substrate and a dielectric layer 1b in contact with the recording layer. The dielectric layer 1a comprises ZnS--SiO.sub.2, and the dielectric layer 1b comprises Si.sub.3 N.sub.4 and/or Ge.sub.3 N.sub.4. The second dielectric layer may comprise a single layer of ZnS--SiO.sub.2, SiO.sub.2 or oxide of a rare earth metal. The second dielectric layer may also comprise a laminate of a dielectric layer 2a comprising ZnS--SiO.sub.2 on the side of the substrate and a dielectric layer 2b comprising SiO.sub.2 or oxide of a rare earth metal on the side of the reflective layer. The dielectric layer 1b has a thickness of 0.

Abstract: A method for preparing an optical recording medium of phase change type is provided. This recording medium comprises a substrate, a recording layer, and a lower and an upper dielectric layers provided in direct contact with the recording layer. In this method, a step of an exposure treatment wherein the surface of the lower dielectric layer is exposed to an oxidative atmosphere is conducted after forming the lower dielectric layer on the substrate and before forming the recording layer on the lower dielectric layer. A step of a heat treatment wherein said lower dielectric layer is heat treated may be carried out in addition to the exposure treatment.

Abstract: The invention provides a phase charge type optical recording medium comprising on both sides of a recording layer dielectric layers, each containing zinc sulfide and silicon oxide as main components. The medium comprises on a substrate 2 a first dielectric layer 31, a recording layer 4, a second dielectric layer 32 and a reflective layer 5 made up of a metal. The first dielectric layer 32 comprises a dielectric lamina 1a on a substrate 2 side thereof and a dielectric lamina 1b on a recording layer 4 side thereof. The dielectric lamina 1a has a silicon oxide content of 2 to less than 40 mol %, the dielectric lamina 1b has a silicon oxide content of 40 to 100 mol %, and the second dielectric layer 32 has a silicon oxide content of 2 to 50 mol % and a thickness of 10 to 35 nm. The number of overwritable cycles can be increased.

Abstract: An optical recording medium of phase change type with an increased number of overwritable operations and method for preparing such an optical recording medium is provided. In the optical recording medium of phase change type whose rate determining stage in the production has been the initialization of the recording layer, the time required for the production is reduced, and stable recording/reproducing properties are realized from the first overwriting operation. The optical recording medium comprises a transparent substrate and a recording layer on the transparent substrate.

Abstract: A magneto-optical disc (1) includes a write/read magnetic layer (4) with high coercivity on a substrate (2) and an auxiliary magnetic layer (6) with low coercivity thereon in a magnetostatically coupled manner. Both the magnetic layers are recorded. Prior to or during reading, an external magnetic field of controlled strength is applied to initialize the auxiliary magnetic layer (6). The recorded magnetization information in the write/read magnetic layer (4) is read out by irradiating reading light from the side of write/read magnetic layer (4). Reading with improved C/N is possible.

Abstract: In an optical recording medium comprising a phase change recording layer on a substrate, the recording layer is essentially of the formula:[{(Ag,Au).sub.a (Sb,Bi).sub.b (Te,Se).sub.c }.sub.1-d (In,Al,P).sub.d ].sub.1-e (Si,Ge,Sn,Pb).sub.ewherein 0.001.ltoreq.a.ltoreq.0.20, 0.40.ltoreq.b.ltoreq.0.90, 0.10.ltoreq.c.ltoreq.0.50, a+b+c=1, 0<d.ltoreq.0.06, and 0.001.ltoreq.e.ltoreq.0.10. The medium can be overwritten at a high linear velocity and remains reliable when stored at elevated temperature.

Abstract: This invention has for its object to provide a magneto-optical recording medium at low costs, which is high in magnetic field sensitivity and reliability, and enables high C/N to be obtained even at high linear velocity.The magneto-optical recording medium of this invention includes on a substrate a first dielectric film, a recording film of a rare earth element-transition element alloy (including Fe), a second dieleetric film containing a metal element M and nitrogen N and a reflective film. In this medium, the recording film is up to 65 nm in thickness, and the respective diffusion indices of oxygen, nitrogen and metal element M in the vicinity of the boundary between the second dielectric and recording films are within the predetermined ranges, when the element distribution is measured by Auger electron spectroscopy under the predetermined conditions. The maximum value of the oxygen content in the vicinity of said boundary is 5 to 25 at %.

Abstract: A magneto-optical disc is fabricated by forming a first dielectric film, a recording film of a rare earth element-transition element alloy, and a second dielectric film on a transparent substrate in the described order and further forming an intermediate film between the recording film and the second dielectric film. The second dielectric film contains at least one metal element and nitrogen. By depositing Ti, Cr or Nb to form an intermediate film of 1-28 .ANG. thick, the disc is improved in magnetic field sensitivity and reliability. By depositing Co or Ni to form an intermediate film of 1-18 .ANG. thick, the disc is improved in magnetic field sensitivity and reproduction stability.

Abstract: In a magnetooptical recording medium comprising a first dielectric layer, a recording layer, a second dielectric layer, a metal reflective layer, and a protective coat on a substrate, magnetooptical recording is carried out in a magnetic field modulation mode using recording light. The first dielectric layer is thinner than the thickness corresponding to the primary minimum reflectivity in the reflectivity versus thickness curve of dielectric layer measured at the light wavelength. This provides an increased recording sensitivity and an increased recording power margin over which recording/reproducing operation can be carried out at low error rates and high resolution.