Variation of the transition temperature in strained epitaxial Y1–xPrxBa2Cu3O7 ultrathin layers

Ultrathin films of Y1–xPrxBa2Cu3O7 (x=0,0.2,0.3) were deposited on perovskite La1.95Sr0.05CuO4, Pr1.95Ce0.05CuO4, and PrxBa2Cu3O7 buffer layers for comparing the effects of epitaxial strain on the superconducting transition temperature (Tc). The resulting changes in Tc demonstrated that in-plane compressive strains improved the superconductivity. The Tc was higher for Y1–xPrxBa2Cu3O7 films grown on PrxBa2Cu3O7 than for films grown on Pr1.95Ce0.05CuO4, which indicates that the variation of Tc in perovskite superconductors is also attributable to factors other than strain, such as interlayer coupling, interlayer strain, and interface roughness.published_or_final_versio