Abstract
dc magnetization measurements in fields up to 5 T on single crystals of reveal a well defined onset of diamagnetism allowing a unique magnetic determination of the upper critical field and its anisotropy. The upper-critical-field slopes are -1.9 and -10.5 T/K corresponding to coherence lengths of 16 and 3 Å for fields perpendicular and parallel to the CuO planes. At the magnetically determined nucleation temperatures no distinct features are found in resistive transition curves.
- Received 28 February 1989
DOI:https://doi.org/10.1103/PhysRevLett.62.1908
©1989 American Physical Society