We report detailed magnetization studies on single-crystal superconductors of -[bis(ethylenedithiotetra- thiafulvalene)]2Cu[N(CN)2]Br with the field H parallel to the b axis (perpendicular to the conducting plane). At high temperatures, the magnetization, M, displays a power-law dependence on H with MHn and n=-2/3. The critical current extrapolated from the width of the hysteresis loop depends on H exponentially. At low temperatures (T<7 K), an anomalous field dependence with a change of sign in the curvature of M(H) is observed. The anomalous field dependence is qualitatively similar to the fishtail magnetization reported for the oxide superconductors. Possible mechanisms giving rise to this effect are discussed.
ASJC Scopus subject areas
- Condensed Matter Physics