ELECTRICAL-PROPERTIES OF Y-BA-NA-CU-O HIGH-TC SUPERCONDUCTORS THIN-FILMS

Y-Ba-Na-Cu-O high Tc superconductors thin films deposited on MgO subst rate by resistive evaporation technique were found to have improved el ectrical properties as compared to pure Y-Ba-Cu-O thin film similarly prepared. A simple conventional inexpensive vacuum system housing a si ngle resistively tungsten heated source was used for the deposition. P ulverized mixture of Y, BaF2, NaF and Cu in the appropriate atomic pro portion was evaporated onto the substrates whose temperature was held constant at 400-degrees-C during the evaporation. In situ heat treatme nt has been carried out at 700-degrees-C under oxygen partial pressure of 7 pa. The films thus obtained were found to have the normal superc onductors orthorhombic phase at room temperature without any further e x situ heat treatment. The films were characterized and analyzed by x- ray diffraction auger electron spectroscopy and four point dc electric al measurements.