PURPOSE: To make a magnetic switching operation possible and to make a high-speed modula tion possible by a method wherein a part which has been installed at one part of a magnetic permeable part conducting a line of magnetic force and which is composed of a superconducting material is phase-shifted by an external field.
CONSTITUTION: Superconducting parts 13, 14 are installed between a magnetic permeable part 11 and a head-tip part 12. A coil 15 is wound on one side of the magnetic permeable part 11, and a DC electric current flows. If the electric current flows to the superconducting part 13 by operating a switch 16, the magnetic flux passes through the inside of the superconducting part 13 and reaches the head-tip part 12. Because the superconducting part 14 displays the complete diamagnetism, the magnetic flux goes out to the outside, and the downward magnetic flux 18 is impressed on a recording medium. It the switch 16 is changed over, the superconducting part 13 displays the complete diamagnetism; the magnetic flux goes out to the outside, returns to the head-tip part 12, and passes through the superconducting part 14 whose superconducting state has been destroyed due to the application of electricity; a loop is formed. At this stage the magnetic flux 19 at the head-tip part is directed upward, and the upward magnetic flux is impressed on the recording medium. By this setup, it is possible to control a direction of the magnetic flux by means of the switch 16 without chang ing the electric current of the coil.
SUKETA YASUSHI
NAKAO TAKESHI
SAITO MAKOTO
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