Calorimetric technique has been used to study AC-field dissipation in ceramic BSCCO samples at low frequencies between 0.05 and 250 Hz at temperatures from 65 to 90 K. In contrast to previous studies the losses have been found to be a nonmonotonic function of field frequency. Frequencies corresponding to local maxima of dissipation depends on temperature and amplitude of AC magnetic field. Flux creep is argued to be at the origin of the behavior. A model connecting the general pattern and location of dissipation maxima with characteristic relaxation times of the system is proposed.
- Flux creep
- Frequency effects