Anomalous flux jump in the organic superconductor K-(BEDT-TTF)2Cu(N(CN)2)Br
Résumé
We study the hysteresis loop of κ-(BEDT-TTF)2Cu(N(CN)2)Br as a function of the thermomagnetic history of the sample. The field-cooled state (fc) always differs radically from that of conventional materials. However, the relaxed magnetization generally coincides with the zero-field cooled (zfc) value, but the transition toward the zfc state is always preceded by strong fluctuations in the measured magnetization.