Anomalous thermal expansion behaviors in Sm-Ba-Cu-O superconductors

Abstract

Linear thermal expansion coefficients α of c-axis oriented Ag-added Sm-Ba-Cu-O superconductors have been measured in the range of 10 — 300 K. The α showed a large bump along the c-axis and a large dent along the ab-plane around 170 – 260 K for the 2 wt% and 5 wt% Ag 2O specimens, but these anomalies essentially disappeared with thermal cycles between room and cryogenic temperatures. In contrast, there were no significant anomalies for the 10 wt% and 20 wt% Ag 2O specimens. These results suggest that the addition of Ag 2O should moderate deformation and help to increase mechanical strength.