PT Journal
AU Sergeev, A
   Semenov, A
   Trifonov, V
   Karasik, B
   Gol'tsman, G
   Gershenzon, E
TI Heat transfer in YBaCuO thin film/sapphire substrate system
SO J. Supercond.
JI J. Supercond.
PY 1994
BP 341
EP 344
VL 7
IS 2
DI 10.1007/BF00724565
DE YBCO films
AB The thermal boundary resistance at the YBaCuO thin film/Al2O3 substrate interface was investigated. The transparency for thermal phonons incident on the interface as well as for phonons moving from the substrate was determined. We have measured a transient voltage response of current-biased films to continuously modulated radiation. The observed knee in the modulation frequency dependence of the response reflects the crossover from the diffusion regime to the contact resistance regime of the heat transfer across the interface. The values of transparency were independently deduced both from the phonon escape time and from the time of phonon return to the film which were identified with peculiarities in the frequency dependence. The results are much more consistent with the acoustic mismatch theory than the diffuse mismatch model.
ER