Accelerator Seminar - Alex Gurevich: Nonlinear Meissner Interferometry using high-Q superconducting cavities

Nonlinear Meissner Interferometry using high-Q superconducting cavities

ABSTRACT

I discuss a nonlinear Meissner interferometry which can be used to measure a nonlinear electromagnetic response of thin film samples and multilayers. Here the input rf field going through a thin film placed at the orifice of a high-Q Nb cavity excites the resonant third harmonic in the cavity because of the nonlinear Meissner in the sample. This interferometer can be used to greatly increase the field amplitude of the nonlinear Meissner effect and generate a giant third harmonic B3ω(T) at GHz frequencies. Measurements of the temperature dependence of B3ω(T)  can reveal the fundamental influence of impurities, grain boundaries and superconducting gap symmetry on the nonlinear Meissner effect in conventional and unconventional superconductors.