Upper Critical Field of Sr_xLa_2-xCuO_4-y

Abstract

The electrical resistance of Sr x La 2- x CuO 4- y has been measured under magnetic fields up to 21.1 T between 4.2 and 50 K. The onset of T c was 41.0 K in H =0 and 33.0 K in H =21.1 T. H 2c (0) is estimated to be 76 T according to the dirty limit theory of type II superconductivity. The H c2 value is near the Pauli limit value and is higher than that (60 T) of PbMo 6 S 8 . Sr x La 2- x CuO 4- y is one of the highest- H c2 superconductor as well as a high- T c one.