Abstract
Transport and thermodynamic properties of a sintered pellet of the newly discovered superconductor have been measured to determine the characteristic critical magnetic fields and critical current densities. Both resistive transition and magnetization data give similar values of the upper critical field, , with magnetization data giving at the transition temperature of . Close to the transition temperature, magnetization curves are thermodynamically reversible, but at low temperatures the trapped flux can be on the order of 1 T. The value of at is estimated to be about , a value similar to classical superconductors like Sn. Hence, the Ginzburg-Landau parameter . Estimates of the critical supercurrent density, , using hysteresis loops and the Bean model, give critical current densities on the order of . Hence the supercurrent coupling through the grain boundaries is comparable to intermetallics like .
- Received 6 February 2001
DOI:https://doi.org/10.1103/PhysRevLett.86.2420
©2001 American Physical Society