Island Growth of Y2BaCuO5 Nanoparticles in (2111.5 nm/12310 nm)xN Composite Multilayer Structures to Enhance Flux Pinning of YBa2Cu3O7-Delta Films

摘要

A controlled introduction of second-phase Y2BaCuO5 (211) nanoparticles into YBa2Cu3O7-8(123) thin films was achieved for the first time for the purpose of increasing flux pinning. The island-growth mode of 211 on 123 was utilized to obtain an area particle density >10(exp 11) sq cm of 211 thick-disk-shaped nanoparticles in individual layers. Composite layered structures of (211y nanoparticles/123z)xN were deposited by pulsed laser deposition on LaA1O3 substrates, with N bilayers = 24 to 100, y thickness = 1 to 2 nm, and z thickness = 6 to 15 nm (assuming continuous layer coverage). With 211 addition, the critical current densities at 77 K were higher at magnetic fields as low as 0.1 T and increased as much as approximately 300% at 1.5 T. The superconducting transition temperature was reduced by approximately 2 to 4 K for 211 volume fraction.