Abstract
ac susceptibility measurements of superconducting powders in magnetic fields to 30 T yield a roughly linear (T) curve extending up to the highest experimental fields. Samples prepared by two different methods give -/dT=2.14±0.08 T/K, with =18.7 K. The observed at low temperatures exceeds the (T) curve from the standard theory by Werthamer-Helfand-Hohenberg. We discuss the role of flux motion and evidence for enhancement of by intrinsic mechanisms such as strong coupling, Fermi surface anisotropy, and/or granularity of the samples.
- Received 29 May 1992
DOI:https://doi.org/10.1103/PhysRevB.46.5876
©1992 American Physical Society