LAALO3-YBCO MULTILAYERS

We have grown HTS bilayers (LaAlO3/YBa2Cu3O7) and trilayers (YBa2Cu3O7/LaAlO3/YBa2Cu3O7) using off-axis rf sputtering from single stoichiometric targets. TEM examination shows that both the LaAlO3 and YBa2Cu3O7 films grow epitaxially upon the preceding layer. The interfaces between layers and at the LaAlO3 substrates are sharp and clean. We find that deposition of the subsequent layers does not degrade the electrical properties of the bottom YBa2Cu3O7 layer; this observation extends to the surface resistance, and to the superconducting transition temperature of the bottom YBCO layer. We discuss the results of the electrical measurements of the multilayer structures made by the off- and on-axis LaAlO3 depositions.