PHOTOACOUSTIC SPECTROSCOPIC ESTIMATION OF HEAT-CAPACITY IN SUPERCONDUCTING YBA2CU3O7 SYSTEM

Using photoacoustic spectroscopic technique we have studied the heat c apacity (C-p) anomaly around 91 K in superconducting Yb2Cu3O7-delta ox ide. The thermal conductivity data required for the estimation of C-p values were taken from other experimental results. The photoacoustic s ignal amplitude is analysed with Rosencwaig and Gersho's (RG) theory. From the value of the ratio of excess heat capacity Delta C-p and supe rconducting transition temperature T-c we estimate the value of the el ectronic specific heat coefficient gamma = 19.98 mJ/mol.K-2 using the relation Delta C-p/T-c = 1.43 gamma (according to the BCS weak-couplin g limit). This value of gamma agrees quite well with those obtained fr om direct heat capacity measurements which vary from 15 to 37 mJ/mol.K -2 (as reported by different research groups).