SIMULTANEOUS MEASUREMENT OF THERMAL-DIFFUSIVITY, THERMAL-CONDUCTIVITY AND SPECIFIC-HEAT BY IMPULSE-RESPONSE PHOTOPYROELECTRIC SPECTROMETRY - APPLICATION TO THE SUPERCONDUCTOR YBA2CU3O7-X

A novel photothermal technique is developed, which enables the simultaneous measurement of the thermal diffusivity alpha, thermal conductivity kappa, and the specific heat C of a sample. The technique is based on frequency-modulated time-delay photopyroelectric spectrometry (FM-TDPS), which consists of chirped laser excitation of the sample and detection of the thermal impulse response by a thin-film pyroelectric detector. No calibration is required for the measurements; absolute values for alpha, kappa, and C may be obtained without having to employ a reference sample. Results on superconducting YBa2Cu3O7-x are reported for the temperature range 50-300 K; the values obtained compare favorably with reported measurements of alpha, kappa, and C for YBa2Cu3O7-x, which previously required separate experiments for their determination.