Substrate Surface Decoration With CeO2 Nanoparticles: An Effective Method for Improving Flux Pinning in Yba2Cu3O7?δ Films

摘要

We have demonstrated improved critical current density, Jc, in YBa2Cu3O7-delta (YBCO) films through a controlled study of substrate surface modifications with nano-sized second-phase pre-formed CeO2 particles. Nanoparticles were applied to single crystal SrTiO3 surfaces using suspension-based techniques prior to YBCO film growth. With the introduction of CeO2 nanoparticles, YBCO films showed more robust field dependence at intermediate fields (Jc prop B-prop), where a smaller power law exponent of alpha ~ 0.3 is obtained. The self-flefd Jc(77K, Bparc) values of the YBCO films on reference and CeO2 modified substrates are 1.1 and 1.9 MA/cm2 ; and at 1 Tesla 0.1 and 0.52 MA/cm2 , respectively. Consistent with this alpha-value, angular field dependent Jc and transmission electron microscopy studies indicate the presence of c-axis aligned correlated defects in these modified samples.