Magnetic field penetration into the high temperature superconductor YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/

The penetration depth of a magnetic field into a superconducting YBa/sub 2/Cu/sub 3/O/sub 7-x/ film was measured by polarized neutron reflection. The sample comprised an epitaxial film with the c-axis of its orthorhombic structure perpendicular to the film's surface. Measurements at 14 K showed that a magnetic field (parallel to the surface) penetrates into the surface over a depth of 1400 /angstrom/. 9 refs., 3 figs