Fabrication of high-critical current density Yba₂Cu₃O_7−δfilms using a fluorine-free sol gel approach

Superconducting Yba₂Cu₃O_7−δ(YBCO) films with critical transition temperatureT_c(0) of 90 K were fabricated via a fluorine-free, metal trimethylacetate based sol-gel route. Precursor films were spin-coated onto single-crystal (001) LaAlO₃(LAO) and (001) SrTiO₃(STO) substrates. Optimization of the burnout process resulted in films with excellent out-of-plane and in-plane texture. Transport critical current densities,J_c, of 1.6 and 1.1 MA/cm²were obtained at 77 K in self-field on films grown on LAO and STO substrates, respectively. This is the first demonstration of high-J_cYBCO film fabrication using a fluorine-free,ex-situprocess.