Insituprocessing of epitaxial Yhyphen;Bahyphen;Cuhyphen;O highTcsuperconducting films on (100)thinsp;SrTiO3and (100)thinsp;YShyphen;ZrO2substrates at 500ndash;650thinsp;deg;C

摘要

We report the formation of excellent quality epitaxial YBa2Cu3O7films on (100)thinsp;SrTiO3and (100)thinsp;ZrO2(yttria stabilized) substrates in the temperature range of 500ndash;650thinsp;deg;C by XECl excimer laser ablation in a 0.2 Torr oxygen ambient. By applying a dc bias voltage of +300 V to an interposing ring, we were able to reduce the substrate temperatures from 650 to 500thinsp;deg;C for obtaining epitaxial films. The quality of the epitaxial films was found to decrease with temperature, particularly below 550thinsp;deg;C. The thickness of the superconducting films was varied from 500 to 5000 Aring; with superconducting transition temperaturesTc(zero resistance) varying from 87 to 90 K for 650thinsp;deg;C deposits. The critical current densityJcof films was found to vary linearly with temperature with values of (zero magnetic field at 77 K) 5.0times;106and 1.0times;106for films deposited at 650thinsp;deg;C on (100)thinsp;SrTiO3and (100) yttriahyphen;stabilized zirconia substrates, respectively. Xhyphen;ray diffraction, transmission electron microscopy, electron channeling patterns, and Rutherford backscattering (RBS)/channeling showed excellent epitaxial quality of films on both substrates with best values of minimum ion channeling yield of 3.5percnt; on (100)thinsp;SrTiO3substrates.