Detection of surface impurity phases in high T.sub.C superconductors using thermally stimulated luminescence

摘要

Detection of surface impurity phases in high-temperature superconducting materials. Thermally stimulated luminescence has been found to occur in insulating impurity phases which commonly exist in high- temperature superconducting materials. The present invention is sensitive to impurity phases occurring at a level of less than 1% with a probe depth of about 1 &mgr;m which is the region of interest for many superconductivity applications. Spectroscopic and spatial resolution of the emitted light from a sample permits identification and location of the impurity species. Absence of luminescence, and thus of insulating phases, can be correlated with low values of rf surface resistance.