HYSTERESIS OF THE MICROWAVE-ABSORPTION IN HIGH-TC SUPERCONDUCTORS

Hysteresis of Josephson microwave absorption (JMA) in the magnetic field by means of standard EPR methodology in ceramic superconducting YBa2Cu3O6.9 is investigated. The hysteresis of JMA strongly depends on 100 kHz modulation amplitude of the external magnetic field and the external magnetic field sweep rate. For a small amplitude (B(m) < 1 G) of the 100 kHz modulation a fast dissipative process, independent on the sweep rate is observed. For B(m) higher than 1 G Josephson-like dissipation occurs. The hysteresis behavior of the JMA disappears for slow enough sweep rate. It disappears also for the magnetic field sweep range lower than +/- 25 G. A phenomenological model for explanation of the observed phenomena is proposed.