RF SUSCEPTIBILITY OF MAGNETRON-SPUTTERED YBA2CU3O7-X FILMS

We measured the complex susceptibility of two different quality magnet ron sputtered YBa2Cu3O7-x films in RF range. Temperature and static ma gnetic field dependence of complex magnetic susceptibility is a useful indicator of appearance of phase coherence in the film including fluc tuation region above T-c. The characteristics showed a low frequency t ype behaviour at loss peak and diamagnetic drop at near transition tem perature and normal state non-zero susceptibility One of our samples d isplayed an enhanced diamagnetism in the normal state close to T-c, wh ich was probably attributed to the combination of the normal skin effe ct and excess conductivity due to superconductive fluctuations. The lo w temperature susceptibility was also frequency dependent and qualitat ively agreed with the vortex-glass scaling model. (C) 1998 Elsevier Sc ience Ltd. All rights reserved.