Optimizing Flux Pinning of YBCO Superconductor With $ \hbox{BaSnO}_{3} + \hbox{Y}_{2}\hbox{O}_{3}$ Dual Mixed Phase Additions

Abstract

Addition of nanophase defects to YBa2Cu3O7 superconductor thin films enhances flux pinning, resulting in an increase in transport current densities (Jct). While previous studies focused on single-phase additions, the addition of several phases simultaneously has shown strong improvements by combining different flux pinning mechanisms. This paper further explores the effect of mixed phase nanoparticle pinning, with the addition of insulating, nonreactive phases of BaSnO3 and Y2O3. Processing parameters vary the BaSnO3 concentration of 3, 5, and 10 vol. %, while maintaining Y2O3 constant at 3 vol.%. Pulsed laser deposition produces films on LaAlO3 and SrTiO3 substrates at deposition temperatures of 750-815°C. Current density is measured for fields ranging from H = 0 to 9 T with H // c, and temperatures from 5 to 77 K, providing a detailed picture of pinning effects. Optimized results of flux pinning, magnetic current densities Jcm (H, T), critical transition temperatures (Tc), lattice parameters, and microstructures are presented.