Applications of high T/sub c/ superconductors to magnetic recording heads

The use of high-T/sub c/ superconductors in high-performance recording heads has been evaluated experimentally and theoretically. Head fields have been measured with Hall elements and inductive pickup loops. The measured fields of a large-scale ring head with Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-x/ in the gap give a supergap permeability of 0.9 when compared to theory. At flying heights of 0.2 mu m, the application to the 3380-type thin-film head results in a theoretical increase in the peak longitudinal field component of over 25%, while the application to the probe-type head given an increase of over 225% in the peak perpendicular field component. For a readback transducer, Josephson junctions in the form of DC-SQUIDS have been made from bulk Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-x/ and experimentally evaluated for application to either the ring- or probe-type head. The break-junctions SQUIDS have a sensitivity of 20 mu V per flux quantum.<>