Capacitance and Resistance Measurement of Au/PrBa_2Cu_3O_y/YBa_2Cu_3O_x Structure at 4.2 K

摘要

The capacitance and the resistance of the Au/PrBa_2Cu_3O_y, (PBCO)/YBa_2Cu_3O_x (YBCO) structure were measured at liquid helium temperature. A film of YBCO was deposited by rf magnetron sputtering at 700℃, and its thickness was 250 nm. A film of PBCO was deposited by rf magnetron sputtering at 690℃, and its thickness was less than 375 nm. The inverse capacitance and the resistance of the structure increased with PBCO thickness when PBCO thickness was more than 70 nm. However, the inverse capacitance was near zero, and the resistance was much less than that of PBCO itself when PBCO thickness was less than 70 nm. These results show the possibility that the electric property of PBCO within 70 nm from the PBCO/YBCO interface is different from that of PBCO itself, that is, there is a low-resistance region in PBCO near the YBCO/PBCO interface.