Microwave standing modes in stacked intrinsic Josephson junction of Bi2Sr2CaCu2O8+x single crystals

Abstract

We studied the distribution of the microwave intensity along the c-axis inside a stack of Bi-2Sr(2)CaCu(2)O(8+x) intrinsic Josephson junctions (IJJs) by monitoring the tunneling critical current of the IJJs with varied microwave power for frequencies in the W band. The stack was microfabricated into a transmission line geometry (15 mum x 0.72 lambdam x 60 nm), with a few-hundred-run thick An layers deposited on top and bottom of the stack. Irradiated microwaves was found to form a standing wave-like mode along the c-axis inside the stack for frequencies above a characteristic cut-off frequency. The information on the microwave distribution in a stack of junctions may be conveniently utilized for high-frequency device applications using IJJs, such as fluxon-flow THz oscillators.