DETERMINATION OF THE C-AXIS THERMAL-DIFFUSIVITY IN YBA2CU3O7-DELTA THIN-FILM BY MIRAGE TECHNIQUE

Superconducting YBa2Cu3O7-delta thin films (similar to 450 nm) are dep osited on LaAlO3 substrates by in-situ dc-magnetron sputtering techniq ue. The thermal diffusivity of the thin films is studied using 'Mirage ' technique. Based upon the effective-sample model the thermal diffusi vity of the constituent materials in the YBa2Cu3O7-delta/LaAlO3 two-la yer system is obtained. It is found experimentally the thermal diffusi vity of single crystal YBa2Cu3O7-delta thin film along c-asis is 0.05 mm(2)/s, much lower than that measured in polycrystalline YBa2Cu3O7-de lta thick film, agreeable to the anisotropy of material. The heat prop agation in high Tc thin films is discussed.