Abstract: A magnetic recording medium which comprises, on a substrate, a Cr undercoat layer and a Co alloy thin film formed on the substrate in this order. The coercive force of the medium is significantly improved by incorporating oxygen either in the Cr undercoat layer or in the Co alloy thin film.

Abstract: A magnetic disc comprises a non-magnetic underlayer formed on a substantially flat surface of a substrate by growing grains of a magnetic material in a circumferential direction of the magnetic disc, and a magnetic layer formed on the non-magnetic underlayer, where the magnetic easy axis of the magnetic layer is oriented in the circumferential direction of the magnetic disc. A method of producing the magnetic disc forms the magnetic layer so that the magnetic easy axis thereof becomes oriented in the circumferential direction of the magnetic disc.

Abstract: A magnetic disc comprises a non-magnetic underlayer formed on a substantially flat surface of a substrate by growing grains of a magnetic material in a circumferential direction of the magnetic disc, and a magnetic layer formed on the non-magnetic underlayer, where the magnetic easy axis of the magnetic layer is oriented in the circumferential direction of the magnetic disc. A method of producing the magnetic disc forms the magnetic layer so that the magnetic easy axis thereof becomes oriented in the circumferential direction of the magnetic disc.

Abstract: A magnetic recording medium for high density recording comprising a non-magnetic substrate, a Cr undercoat and a magnetic Ni-Cr-Co alloy thin layer formed on the substrate. The magnetic alloy thin layer has a thickness of from 400 to 1200 angstrom and a Cr content of from 3 to 17 atomic percent. As a result, improved magnetic characteristics and corrosion resistance of the medium are ensured.

Abstract: A magnetic medium for horizontal magnetization recording which comprises a non-magnetic substrate and a magnetic recording film formed on at least one side of the substrate, is described. The magnetic recording film consists essentially of an amorphous Co-Cr alloy containing from 5 to 15 atomic percent of oxygen atom. A method for making the above type of medium is also described in which the magnetic film is vapor deposited under conditions of a partial pressure of oxygen gas of 1.times.10.sup.-3 to 3.times.10.sup.-3 Torr., and a sputtering rate of from 0.05 to 0.15 .mu.m/minute.

Abstract: A magnetic medium for horizontal magnetization recording which comprises a non-magnetic substrate and a magnetic recording film formed on at least one side of the substrate, is described. The magnetic recording film consists essentially of an amorphous Co-Cr alloy containing from 5 to 15 atomic percent of oxygen atoms. A method for making the above type of medium is also described in which the magnetic film is vapor deposited under conditions of a partial pressure of oxygen gas of 1.times.10.sup.-3 to 3.times.10.sup.-3 Torr., and a sputtering rate of from 0.05 to 0.15 .mu.m/minute.

Abstract: A magnetic recording medium comprises a base, a magnetic layer made of a magnetic material and formed on the base, a lubricant layer made of a lubricant material having lubricity and formed on the magnetic layer, and a corrosion resisting layer made of a corrosion resisting material having corrosion resistance and formed on the lubricant layer. An additional corrosion resisting layer made of a corrosion resisting material having corrosion resistance may be provided between the magnetic layer and the lubricant layer.

Abstract: A magnetic recording medium of the type which comprises a non-magnetic support, and a thin magnetic metal layer formed on at least one surface of the support is described. The magnetic metal layer is protected with a carbon nitride layer.

Abstract: Magnetic recording media for high density recording having a much improved coercive force comprise a non-magnetic substrate and a magnetic thin film formed on at least one side of the non-magnetic substrate. The magnetic thin film consists essentially of a magnetic material and a tungsten oxide used in an amount of up to about 50 wt %, calculated as W, of the magnetic thin film. A method for making the media is also described.

Abstract: A magnetic metallic powder comprising iron or iron-cobalt as its fundamental component and, besides, molybdenum in an amount of 0.05 to 5% by weight of the fundamental component. The magnetic powder is produced by heat reduction of a molybdenum-doped iron oxide powder which may optionally contain cobalt. The presence of molybdenum suppresses agglomeration of the heated particles and produces an improvement on the coercive force of the metallic powder.

Abstract: A magnetic recording medium which comprises a support, and a magnetic recording layer formed on the support, the magnetic recording layer being comprised of a major proportion of a magnetic metal powder and minor proportions of a metal oxide powder, the metal oxide powder serving as a wear-resistant agent, an organic binder and ethylene stearyl bisamide serving as a lubricant.

Abstract: A magnetic metallic powder which is essentially of iron or its alloy with at least one other metal and features a good resistance to oxidation by air as well as a large value for saturation magnetization is obtained by the reduction of an oxide powder prepared or treated in a basic liquid phase environment the oxide powder ultimately to have a pH value not smaller than 6.0. A magnetic recording medium consisting of a nonmagnetic base and a thin magnetic layer comprising the metallic powder dispersed in a polymer binder serves for high density recording purposes and long retains its excellent physical properties.