A new method for a local study of nonlinear microwave properties of superconductors

We report a set of experimental data on local third-harmonic generation at microwave frequencies (0.5 GHz) in $YB{a}_{2}C{u}_3{O}_7$ and Nb films. For local investigations of the nonlinear response a probe with inductive coupling was elaborated. The map of the nonlinear microwave response of a $YB{a}_{2}C{u}_3{O}_7$ thin film is plotted below $T_c$ with high resolution. The third-harmonic power is measured as a function of temperature, input power and dc magnetic field at some areas of the film. The correlation between the depinning current density $J_p$ and the nonlinear microwave response is also demonstrated.