STOICHIOMETRIC EFFECTS IN EPITAXIAL BA2-XY1-YCU3-ZO7-DELTA THIN-FILMS ON LAALO3(100)

Stoichiometric deviations of up to ±5% in Ba2YCu3O7-δthin films grown by coevaporation on LaAlO3(100) substrates are found to cause (1) a decrease of the critical current density (Jc) of up to an order of magnitude, (2) a depression of the critical temperature (Tc) and a broadening of the superconducting transition width (AT), (3) a deterioration of the surface morphology, and (4) a decrease in the crystallinity of the films. The data indicate that composition deviations of greater than ±1% result in degradation of film quality. These findings have significant implications for the degree of composition control required during deposition to produce films with optimized properties. © 1990, Materials Research Society. All rights reserved.