Anomalous temperature dependence of Hc2 in BiSrCuO

Abstract H c2 ( T ) has been measured for thin BSCO films at temperatures down to 65 mK and pulsed fields up to 35 T. H c2 ( T ) diverged anomalously as the temperature decreased: at the lowest temperature, it was five times that expected for a conventional superconductor. Although deviations from the conventional behavior have been observed in other superconductors, such strong divergence over such a large range of reduced temperature has not been seen before.