Heteroepitaxial growth of strained multilayer superconducting thin films of Nd_1.83Ce_0.17CuO_x/YBa₂Cu₃O_7-δ

Heteroepitaxial growth of strained multilayer thin films of YBa₂Cu₃O_7-δ/Nd_1.83Ce_0.17CuO_x by pulsed-laser deposition is reported. The coherency strain results in biaxial compression of the tetragonal Nd_1.83Ce_0.17CuO_x layers, whereas the biaxial tension in the YBa₂Cu₃O_7-δ layers removes the orthorhombic distortion and makes the unit cell isotropic in the basal plane (a=b). Depending on their oxygen content, either the YBa₂Cu₃O_7-δ or the Nd_1.83Ce_0.17CuO_x layers are superconducting in these multilayers. The strain-induced structural modification has a significant influence on the superconducting transition temperature of the YBa₂Cu₃O_7-δ layers.