Electrical characteristics of Pb0.92La0.08(Zr0.52Ti0.48)O3/YBa2Cu3O7-x heterostructures.

Pb 0.92 La 0.08 (Zr 0.52 Ti 0.48)O 3 /YBa 2 Cu 3 O 7-x (PLZT/YBCO) heterostructures with high c-axis epitaxial properties were prepared by PLD method. Hysteresis loops, photovoltaic effects, and current transfer properties of this structure were investigated. Hysteresis loop test results showed that residual polarization intensity of PLZT gradually decreases with decreasing temperature but coercivity field increases. I–V curve of PLZT/YBCO heterostructure in dark state was tested and found to have significant rectification characteristics, indicating the existence of potential barrier at interface of the heterostructure. UV illumination experiments showed that PLZT/YBCO heterostructure has clear photovoltaic effect, with both photovoltage and photocurrent decreasing as the temperature is decreased. Moreover, photovoltage and photocurrent display jump phenomenon when superconducting transition of YBCO occurs. Further analysis of jump phenomenon revealed that the difference of photovoltage with temperature before and after superconducting transition of YBCO is consistent with superconducting energy bandgap of YBCO. The opening of superconducting energy gap of YBCO lowers PLZT/YBCO interfacial potential barrier and promotes migration of photogenerated carriers, consequently increasing photovoltage and photocurrent. This work describes novel method to measure superconducting energy gap. [ABSTRACT FROM AUTHOR]