Effect of magnetic field on the photovoltaic properties of YBa2Cu3O6.96/Ag heterojunction

Abstract

The obvious photovoltaic effect (Voc ∼ 30 μV) induced by purple-laser illumination at high Tc superconductor YBa2Cu3O6.96/Ag (YBCO/Ag) heterojunction has been observed, revealing that there exists an electrical field across the YBCO/Ag interface. It has been found that magnetic field can dramatically change the photo-induced voltage in the vicinity of superconducting transition. With increasing magnetic fields up to 3 T, the photovoltage at 74 K and 30 mW/mm2 is reduced from 15 μV to zero and then reaches −15 μV. The polarity of the voltage can be switched by applying an external magnetic field, as well as by varying the laser intensity. Our results can be understood in terms of the magnetic vortex penetrating in high Tc superconductors and provide strong evidence for the existence of an interface electrical field in the superconductor/metal heterojunction.