FLUX-PINNING IN HIGH-T-C SUPERCONDUCTIVE FILMS

Magnetization measurements have been performed on c-axis oriented Y- a nd Gd-based superconductive films in a wide range of the temperatures T (4.2-85 K) and magnetic fields H (O-8 T) with H parallel to c-axis. The influence of flux creep on both the temperature dependence of crit ical current density J(cm) and the scaling behavior of flux pinning fo rce F-P has been discussed in detail. The experimental results show th at Y and Gd films have different pinning mechanism. Flux pinning-force peaks in high fields are observed in Gd film at high temperatures and can be considered as evidence for collective pinning.