Growth and transport properties of multilayer superconducting films of Nd_1.83Ce_0.17CuO_x / YBa₂Cu₃O_7-δ

Strained multilayer thin films of YBa2Cu3O7-δ/Nd1.83Ce0.17CuOx have been prepared by laser ablation deposition. For individual layers below a critical layer thickness of about 250angstrom, coherency strain compresses orthorhombic distortion in the YBa2Cu3O7-δ layers is also removed. Depending on their oxygen content, either the YBa2Cu3O7-δ or the Nd1.83Ce0.17CuOx layers are superconducting in these multilayers. The strain-induced structural modification has a significant influence on the superconducting transition temperature and critical current density of the YBa2Cu3O7-δ layers. Zero field critical current densities as high as 1.1×107A/cm2 at 77K have been measured for the YBa2Cu3O7-δ layers.