Preliminary measurements of the low frequency impedance of superconducting epitaxial Y-Ba-Cu-O films

The authors have produced epitaxial thin films of superconducting Y-Ba-Cu-O grown onto (110) and (100) oriented SrTiO3 and MgO substrates by in situ RF sputter deposition. The impedance of the films has been measured and the results compared with two-fluid theory. The impedance of the films depended strongly on crystallographic orientation. Between room temperature and the critical temperature Tc the film reactance was inductive for well orientated (100) films and capacitive for (013) orientated films. The films were purely inductive for temperatures below Tc, with a constant value equal to the film inductance after flux exclusion due to the Meissner effect.