Microwave properties of high-temperature Josephson contacts on a sapphire bicrystal substrate

Resumo

HTS bicrystal junctions up to 50 μm wide on sapphire substrates have been studied. The dependences of the critical current on the temperature and external magnetic field of these contacts have been measured. The irradiation of the Josephson junction on a sapphire substrate at the frequency of 73 GHz at the temperature of 77 K resulted in the appearance of Shapiro steps in the current–voltage characteristic (IVC) at the voltage of 150 μV. The possibility of using such contacts in voltage standards at the temperature of 77 K in the ranges of microwave and terahertz frequencies has been analyzed.