Angular dependence of J c in YBCO films with c-axis correlated nano-rods and in-plane-distributed nano-particles

The quasi-multilayered films consisting of YBa2Cu3O y layers with BaSnO3 nano-rods and the pseudo layers of in-plane-distributed BaSnO3 nano-particles were fabricated using a PLD method, in order to clarify the pinning landscape simultaneously improving the critical current densities, J cs, both at B || c and at B || ab. The insertion of the pseudo layers into YBa2Cu3O y films contributes to the enhancement of J c at B || ab but it is a tendency to reduce the J c at B || c. When the density of the nano-particles per layer is decreased, by contrast, the J c at B || ab can be enlarged without the reduction of the c-axis peak. This is attributed to the fragmentation of the channel for flux creep motion through the pseudo layers. Furthermore, the J c in tilted magnetic fields off the c-axis enhances as well as c-axis peak in a high magnetic field, when BaSnO3 nano-particles are increased.