Heat-capacity investigations near the normal-superconducting transition ofYBa2Cu3O7

Abstract

A high-resolution ac quasiadiabatic calorimeter has been employed to measure the heat-capacity anomaly associated with the normal-superconducting transition of several slightly twinned ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ single-crystal samples. The heat-capacity anomaly from one of the samples displays a very sharp 10–90% jump on the high-temperature side of anomaly and can be described by a mean-field model based on the BCS theory.