Anomalies in elastic and thermal properties associated with the superconducting transition of single crystal Bi2Sr2CaCu2Oy

Abstract

The authors have measured the in-plane Young's modulus sound velocity ve(T) at kHz frequencies and the specific heat Cp(T) of Bi2Sr2Ca1Cu2Oy single crystals with Tc=93.2 K. In the region of Tc a softening is observed in ve, corresponding to a discontinuity in dlnve/dT of 6.2 ppm/K and an indication of a change of Delta ve/ve of the order of 10 ppm. From Delta Cp/Tc approximately=16 mJ/(molK2) they find mod delta Tc/ delta sigma i mod approximately=0.1 K/kbar and - delta 2Tc/ delta sigma 12 approximately=10-3-10-2 K/kbar2 (i=1,2).