SUPERCONDUCTIVE SIGNAL DETECTING ELEMENT

摘要

PURPOSE:To realize the highly sensitive reproduction of signals on a narrow track by adding a magnetic shield made of a soft magnetic material containing a nonmagnetic pole part to a magnetic flux quantum element via a nonmagnetic layer. CONSTITUTION:A DC magnetic flux quantum element (SQUID) part includes a magnetic flux detection loop 2, a Josephson junction part 3 and an electrode terminal 4. A magnetic shield consists of a soft magnetic shield 11 and a nonmagnetic hole part 12. The SQUID part is separated from the magnetic shield via a nonmagnetic layer for constitution of a superconductive signal detecting element. Thus the part 12 formed at a part of the shield 11 functions as a data which transmits selectively the magnetic fluxes produced from a medium. The magnetic lux, i.e., the magnetic potential difference is turned into a differential by the size of the part 12 and detected. Thus the reproduction of signals is carried out in the exactly same way as a conventional head.