Investigation on the Current Transport Characteristics of SrTiO3/YBa2Cu3O7-x Heterostructure

By the combined use of the sol-gel and pulsed laser deposition methods, the SrTiO3/YBa2Cu3O7-x (STO/YBCO) heterostructure was prepared on a LaAlO3 substrate. XRD results and phi scanning test showed that the prepared STO/YBCO heterostructure had good biaxial texture. Moreover, a Pt electrode was sputtered on the STO/YBCO heterostructure to investigate the current density-voltage (J - V) characteristic curves of STO/YBCO in the 50-300 K temperature range. The results showed that the STO/YBCO heterostructure had good rectifying characteristics. With an applied positive bias voltage smaller than 3.7 V, the current density of the STO/YBCO heterostructure decreased with the decrease of temperature; for higher voltages, on the contrary, the current density increased with the decrease of temperature. When the YBCO experienced superconducting transition, the turn-on voltage (V (t)) changed suddenly due to the sudden opening of the superconducting energy gap of YBCO. The V (t) variation obtained from the experiment was essentially consistent with the known value of the YBCO superconducting energy gap.