Magnetic field penetration into the high temperature superconductor YBa₂Cu₃O_7-x

The penetration depth of a magnetic field into a superconducting YBa2Cu3O7-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 Å. © 1989.