Preparation And Electrical Properties Of PZT(PLZT)/YBCO Heterostructure

The unique charge transport characteristics of the fcrroclectric/superconducting heterostructure interface lead to some new physical phenomena.Study of these physical phenomena is not only helpful to further understand the mechanism of high temp erature superconductivity,but also can promoting the industrial application of superconducting microelectronic devices.Therefore,in this paper,YBa2Cu3O7-δ(YBCO)is superconduction layer,Pb(Zr0.52,Ti0.48)O3(PZT)is fcrroelectric layer to fabrication of ferroelectric/superconducting heterostructure to study on the charge transport characteristics and interaction between the interfaces of heterostructure.The main research contents of this article are as follows.The c-axis oriented YBCO fine pattern was prepared on LaAlO3(LAO)substrate by photosensitive sol-gel(sol-gel)method.The R-T test indicated that the superconducting transition temperature Tc was about 89 K.Pb(Zr0.52Ti0.48)O3(PZT)thin films were prepared by pulsed laser deposition(PLD)method on YBCO pattern to form PZT/YBCO heterostructurc.XRD test showed that the PZT/YBCO heterostructure had good c-axis orientation.Pt/PZT/YBCO heterojunction formed Pt top electrode by sputtering method.The J-V and P-V characteristics of heterojunction were studied in the range of 80～300 K.The study of J-V characteristics showed that when the temperature is greater than 150 K,the charge transport characteristic of heterojunction was SCLC mechanism.When the temperature is less than 150 K and the voltage is greater than 3 V,the charge transport characteristic of heterojunction is SE mechanism.When the temperature is less than 150 K and the applied voltage is less than 3 V,the charge transport characteristics of heterojunction conform to the SCLC mechanism.The study of P-V properties show that heterogeneous junction Pr increases and then decreases with the decrease of temperature,meanwhile Ec increases with the decrease of temperature.The test results of the modulation effect of extermal field on YBCO superconducting transition temperature Tc show that as the external field increases when the external field takes YBCO as high potential.When Pt is the high potential of the external electric field,Tc of YBCO does not change with the electric field because the schottky barrier height on one side of YBCO remains unchanged.In addition,the modulation effect of the external electric field near the YBCO superconducting transition temperature on the YBCO resistance further verifies the above Tc modulation experiment results.The PLD method was used to prepare(Pb0.92La0.08)(Zr0.52Ti0.48)O3/YBCO double layer film on the LAO substrate.The P-V measurements show that heterostructure have good ferroelectricity.After polarizing the heterostructure open circuit voltage Voc under ultraviolet light has a strong dependence on the residual polarization strength of PLZT.Voc decreases gradually with the decrease of temperature,and near the YBCO superconducting transition temperature(about 90 K),the superconducting transition leads to a sharp change in the electrical properties of YBCO,and the Voc show a mutation process.