The abnormal temperature-dependent rectification effect in BiFeO3/YBa2Cu3Oxheterostructures

We report the fabrication and properties of heterostructures formed by the BiFeO3 (BFO) ferroelectric and YBa2Cu3Ox (YBCO) superconductor. Four measurement configurations on BFO/YBCO heterojunctions are proposed and showed different I-V characteristics. Moreover, one type of BFO/YBCO heterostructures which had the strongest rectification effect at 15K, showed the abnormal rectification effect dependent on temperature. The rectifying effect enhanced with decreasing temperature below the superconducting transition temperature of YBCO. YBCO electrode played an important role in increasing the rectifying parameter because of the high density of states for quasi-particles in YBCO in the superconducting state.