Thermal boundary resistance for YBa2Cu3O7−δ films

We have made direct measurements of the thermal boundary resistance, Rbd, between high quality epitaxial films of YBa2Cu3O7−δ and a variety of substrates with and without buffer layers. The boundary resistance was deduced from measurements of the electrical resistance changes in three parallel strips of YBa2Cu3O7−δ when one was electrically heated. Our measurements indicate that Rbd is weakly dependent on temperature and, for all the measured samples, has a value of 0.8–1.4×10−3 K cm2/W between 90 and 200 K, which is a factor of ≊80 larger than the prediction of the acoustic mismatch model at 100 K. The thermal response time of ≊1 ns which results from the heat capacity of the film and Rbd is observed in many experiments with pulsed laser sources.