Harmonic frequency mixing in Bi2Sr2CaCu2O8+X intrinsic Josephson junctions
H. B. Wang, Yuta Aruga, T. Tachiki +5 more
In a c-axis junction stack (10 μm×10 μm in a-b plane) patterned on a Bi2Sr2CaCu2O8+X single crystal, we performed harmonic mixings between a 100 GHz signal and up to the 98th harmonic of a local oscillator at about 1 GHz. The dependence of PIF on V, where PIF is the mixing output at the intermediate frequency and V is the dc voltage across the junction stack, was strongly affected by the local oscillator power levels. For low values of local oscillator power, the optimum operation point where PIF became maximum was around zero bias, and typical multi-branch structure of PIF vs V curves were observed. For high values of local oscillator power, the optimum operation point moved to the high-voltage region. In both cases, interesting oscillations occurred on the PIF vs V curves. Our experimental results led us to believe that intrinsic Josephson junctions can be good candidates for high frequency applications and the harmonic mixing may be a useful probe to investigate plasma phenomena in the layered superconductors.
Applied Physics Letters•Oct 11, 1999•11 citations