Controlled superconductivity in infinite-layer Sr_(0.875)La_(0.125)CuO_2 films sputter-deposited on Ba_ySr_(1-y)TiO_3 buffer layers

摘要

We present a systematic study of the structural and electrical properties of electron-doped infinite-layer Sr_(0.875)La_(0.125)CuO_2 (SLCO) thin films grown on Ba_ySr_(1-y)TiO_3 (BSTO; y= 0.2-0.7) buffer layers. The BSTO (y = 0.2-0.6) buffer layers were found to allow the coherent growth of SLCO thin films. The coherently tensile-strained SLCO thin films grown on BSTO (y = 0.6) buffer layers at a low deposition rate of 0.2 nm/min showed a low room-temperature resistivity (118 μΩ cm) and a high T_c (36 K). All the other SLCO thin films exhibited a reduced T_c of around 20 K. The present results are discussed in terms of correlation among epitaxial strain, c_(SLCO)/a_(SLCO) ratio, and T_c.