Heteroperovskite phase formation and magnetotransport properties of YBa2Cu3O7−x/SrRuO3 quasimultilayers

A series of quasimultilayers consisting of YBa2Cu3O7−δ (YBCO) and SrRuO3 (SRO), namely, p×(YBCO(m)/SRO(n)) (p: repetition periods; m: YBCO pulse number; n: SRO pulse number), is prepared on single crystal SrTiO3 by pulsed laser deposition. X-ray diffraction measurements reveal that a heterogeneous phase of Ba2YRuO6 is formed due to the chemical reaction, while both the in-plane and out-of-plane textures of the present quasimultilayers are as good as in the pure YBCO films. The content of Ba2YRuO6 increases as the pulse number of SRO increases, leading to the decrease in superconducting transition temperature (Tc). There is no obvious difference in Tc between the samples with the different deposition sequence orders of YBCO and SRO. The magnetic field dependence of critical current density (Jc) shows an enhanced flux pinning at relatively high fields for all the present quasimultilayers, which occurs at different ranges of fields depending on the applied temperatures. The Jc of the quasimultilayers can reach two times higher than that of pure YBCO films in a wide range of magnetic fields, which shows the promising application for coated conductors.