Difference Between ${\rm BaSnO}_{3}$ and ${\rm BaZrO}_{3}$ Nano-Rods for C-Axis-Correlated Pi

In order to understand the vortex pinning properties by the BaZrO₃ (BZO) and BaSnO₃ (BSO) nano-rods in Er123 films, the microstructure and the angular dependence of J _c and resistivity were measured in detail for the BZO and the BSO added Er123 films with the similar matching field prepared by pulsed laser deposition. We found that the peak at B //c in the angular dependence of J _c for the Er123 film with BSO nano-rods was higher in a wide magnetic field region up to the irreversible field than that for the Er123 film with BZO nano-rods, although the minimum values of the angular dependence of J _c are similar each other. Hence, the BSO nano-rods work more effectively as the c -axis-correlated pinning center than the BZO nano-rods because of the different elementary pinning energy of nano-rods.