Heat capacity peculiarity of 90 K samples of YBa2Cu3O6+x above Tc

Abstract The temperature dependence of heat capacity of superconducting YBa 2 Cu 3 O 6+ x system (with x =0.85, 0.90, 0.95) was investigated above T c . For all the samples the “small” anomalies were discovered in ranges 110–180 K ( T low ), 205–235 K ( T m ) and 250–290 K ( T h ). The analysis with involving data for TmBa 2 Cu 3 O 6.95 and GdBa 2 Cu 3 O 6.95 reveals that one may consider some of these anomalies as a characteristic property of the 90 K samples.