Enhancement of critical current density of YBCO films by introduction of artificial pinning centers due to the distributed nano-scaled Y2O3 islands on substrates

Abstract We introduced high-density extended crystalline defects, which result in artificial pinning centers of the quantized vortices, into c -axis oriented YBa 2 Cu 3 O 7− x (YBCO) films. The crystalline defects created perpendicular to the film surface were derived, during the film deposition process, by the distributed nano-sized Y 2 O 3 islands prepared on SrTiO 3 (1 0 0) substrates. The Y 2 O 3 nano-islands were approximately 3 nm in height and 25 nm in diameter and the density was controlled from about 89 to 212 μm −2 by choosing the Y 2 O 3 deposition condition. J c s of YBCO films grown on SrTiO 3 substrates with the extended defects were increased by about 150% higher than those of YBCO films without the defects.