Abstract: [Solving Means] A method of producing a magnetic powder includes: coating a surface of each of silica-coated precursor particles with at least one type of coating agent of a metal chloride or a sulfate; and firing the precursor particles coated with the coating agent.

Abstract: [Solving Means] A method of producing a magnetic powder includes: coating a surface of each of silica-coated precursor particles with at least one type of coating agent of a metal chloride or a sulfate; and firing the precursor particles coated with the coating agent.

Abstract: A thin film type magnetic head that electromagnetic conversion efficiency is improved by making gradually magnetic resistance larger with approaching to a magnetic gap can be provided. There is disclosed a magnetic head including a pair of magnetic core half members having nonmagnetic substrates and magnetic metal films formed on the nonmagnetic substrates and a coil formed at a concave part by a thin film forming process, the pair of magnetic core half members being jointed to each other opposite to each other through a magnetic gap formed between the respective magnetic metal films, the concave part formed on the surface formed by joining at least one of the magnetic metal films and the other magnetic metal film, wherein assistant cores consisting of magnetic materials are joined on the side of the surface by joining a pair of nonmagnetic substrates and the magnetic metal films are formed connected with the assistant cores.

Abstract: A rotary magnetic head apparatus is provided which is capable of reliably supplying DC power for driving to an active-type reproducing head provided within a rotary drum and which is capable of taking the reproductive output signal of the active-type head to the outside of the drum. The rotary magnetic head apparatus includes a fixed drum, a rotary drum which is rotatable with respect to the fixed drum, an active-type reproducing head, disposed on the rotary drum, for reproducing information from a magnetic tape, a constant-current circuit, disposed on the rotary drum, for supplying a constant current for driving the head to the active-type reproducing head, a noncontact signal transmission device for taking the reproductive output signal which is output when the active-type reproducing head reproduces information from the magnetic tape to the outside of the rotary drum, and a sliding-type contact device for supplying external DC power to the constant-current circuit.

Abstract: A magnetic head according to the present invention can generate excellent readout output even with a reduced track width by controlling the stress applied to the half magnetic cores from the glass. The magnetic head comprises a pair of magnetic cores made of ferromagnetic oxide, at least one of which has a groove for a coil and which are bonded together with the glass with a gap material in-between, wherein the coefficient of thermal expansion of the glass to bond magnetic cores together is smaller than that of the ferromagnetic oxide by 20.times.10.sup.-7 to 35.times.10.sup.-7 per degree Celsius.

Abstract: A magnetic head has a pair of magnetic core substrates formed of an oxide magnetic material, at least one of the magnetic core substrates having a gap film formed on an abutment surface thereof, the pair of magnetic core substrates being abutted to each other on the gap film as abutment surfaces, having a magnetic gap formed between them. The gap film is formed of platinum, the platinum group, or an alloy consisting mainly of platinum or the platinum group. The pair of magnetic core substrates are bonded to each other to be integrated into one unit by a non-magnetic glass. The magnetic gap has a track width of not greater than 50 .mu.m. The gap film has a thickness of not greater than 150 nm.