Microwave detection properties of asymmetrically narrowed YBa2Cu3O7–x structures

Abstract

Results of our research demonstrate possibilities of detection of microwaves radiation by means of asymmetrically narrowed YBa2Cu3O7-x oxygen-rich (x ≤ 0.2) and oxygen-decomposed (x > 0.5) in the necked region at temperatures higher than the critical temperature of the superconductor Tc at which superconductor exhibits properties of a heavily-doped semiconductor. Both types of structures, mounted into a 10 GHz waveguide, generate sub-linearly increasing amplitude of detected voltage with increase of incident power of pulsed 10-GHz-frequency microwave radiation. The voltage sensitivity Sx ≤ 0.2 ≥ 1.3 mV/W of oxygen-rich and Sx > 0.5 ≥ 9 mV/W of oxygen-decomposed structure were measured at room temperature. Asymmetrical shape of nonlinear current-voltage dependences depends on oxygen content x in the necked region and temperature of the tested structure. Our results show that the asymmetrically narrowed structure with a necked region down to 10 μmm made of partially deoxygenated YBa2Cu3O7–x superconductor can be used as a nonsuperconducting, nonlinear on-chip element (detector of MW power) in the YBa2Cu3O7–x chip operating at temperatures below critical temperature Tc of the chip superconductor.