Measurement of the specific-heat anomaly at the superconducting transition ofYBa2Cu3O7−δ

Abstract

The specific heat of the ceramic superconductor $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ has been measured in the vicinity of the transition temperature $T_c=90\mathrm{}$ K, using a combination of ac and heat-pulse calorimetry. A step change $\Delta C_p=6.2\mathrm{}$ mJ/gK is observed at $T_c$ which, when divided by the electronic contribution to the heat capacity estimated from susceptibility data, gives a value close to that expected from Bardeen-Cooper-Schrieffer (BCS) theory. These results confirm that the material is a bulk superconductor with BCS-like behavior. The lattice contribution can be fitted to a Debye specific heat with ${\ominus }_D\approx 440$ K.