]Influence of misorientation angle on third harmonic voltages V3 induced by YBCO thin films on bi-crystal substrates

YBa2Cu3Oy thin films have been deposited on SrTiO3 bi-crystal substrates with various misorientation angles and a STO single-crystal substrate by a pulsed laser deposition method. The magnetic field dependence of third harmonic voltage V3 vs. coil current I0 was measured by the third harmonic voltage method when the coils were mounted on the crystal grain boundary. The V3 increases monotonically with increasing I0 in the single-crystal substrate. However, the V3 increases strangely with increasing I0 in the bi-crystal substrate with low-angle grain boundary in low-magnetic fields. On the other hand, the V3 increases monotonically in the bi-crystal substrates with high-angle grain boundary.