ANOMALOUS TEMPERATURE DEPENDENCE OF THE UPPER CRITICAL MAGNETIC FIELD IN ELECTRON-DOPED HIGH-TEMPERATURE SUPERCONDUCTOR

摘要

We present resistivity measurements of the upper critical field as a function of temperature for Nd_(2-x)Ce_xCuO_(4+δ)/SrTiO_3 single crystal films near antiferromagnetic-superconducting phase boundary (x = 0.14) in magnetic fields up to 90kOe at temperatures down to 0.7K. The data are well described by a two-band/two-gap model for a superconductor in the dirty limit.