Optimizing Flux Pinning of YBCO Superconductor With \hbox + \hbox\hbox Dual Mixed Phase Additions

Addition of nanophase defects to YBa 2 Cu 3 O 7 superconductor thin films enhances flux pinning, resulting in an increase in transport current densities ( J ct ). 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 BaSnO 3 and Y 2 O 3 . Processing parameters vary the BaSnO 3 concentration of 3, 5, and 10 vol. %, while maintaining Y 2 O 3 constant at 3 vol.%. Pulsed laser deposition produces films on LaAlO 3 and SrTiO 3 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 J cm ( H, T ), critical transition temperatures ( T c ), lattice parameters, and microstructures are presented.