CHARACTERIZATION OF THIN-FILMS OF YBA2CU3O7-DELTA USING AN INTERDIGITAL RADIO-FREQUENCY PROXIMITY PROBE TECHNIQUE

A capacitively coupled interdigital probe technique is described where by the electrical characteristics of thin films at arbitrary frequenci es in the range from about 100 kHz to beyond I GHz may be studied. Pat terning of the film, deposition of electrodes, and bonding of electric al leads are unnecessary, so that all measurements are nondestructive and noninvasive. Preliminary measurements of the superconducting trans ition in thin films of the high-temperature superconductor YBa2Cu3O7-d elta in magnetic fields up to 1.5 T are presented and discussed. They show a large held-dependent peak, attributable to tunneling effects, j ust below the onset temperature. Anomalies are also seen at higher tem peratures, providing evidence of a structural phase transition. (C) 19 97 American Institute of Physics.