Flux Pinning of Y-Ba-Cu-O Films Doped With BaZrO3 Nanoparticles by Multilayer and Single Target Methods (Postprint)

The superconducting properties of YBa2Cu3O7-x (YBCO or 123) thin films doped with BaZrO3 (BZO) nanoparticles by multilayer and single-target methods were studied and compared. Thin films of 123 + BZO were processed by pulsed laser deposition on LaAlO3 and SrTiO3 single crystal substrates. Multilayer (BZO 0.6 nm - 1.4 nm /23(sub 15) nm)19 structures were grown by alternating deposition from 123 and BZO targets, and BZO additions of 0-2 Vol% were deposited using (1231(sub 1-x) BZO(sub x)) single-targets. The multilayer and single-target methods of BZO addition caused significant differences of superconducting transition temperatures (Tc) measured by AC susceptibility, and critical current densities (Jc) measured by both magnetic and transport methods as a function of temperature (T), applied magnetic field (H) and angle of H field incidence (theta). Single-target films had almost linear decrease of Tc and self-field Jc with BZO vol% addition, and compared to multilayer films had lower Jc(77 K, H 4 T) however had improved high-field properties for Jc(77 K, H 4 T). Multilayer films had almost no decrease of Tc and self-field Jc for high BZO additions up to 10 Vol% and very strong peak of Jc(H ab in - plane) and constant and high Jc(H, 0 80 deg.). Single-target BZO-2 Vol% films had slightly enhanced Jc(H c - axis), consistent with results by other authors. Prepared in collaboration with Los Alamos National Laboratory, Los Alamos, NM, and University of Dayton Research Institute, Dayton, OH. Published in IEEE Transactions on Applied Superconductivity, Vol. 17, No. 2, p3724-3728, June 2007.