High-order harmonic generation from inhomogeneous high-Tc superconducting films

The generation of high-order harmonics from inhomogeneous ion implanted YBCO films has been investigated by monitoring its response to an alternating magnetic field. These harmonics are generated because of the high nonlinearity caused by sudden magnetic flux penetration above the first critical field. Harmonics up to 100th order and interference effects were observed. The measurements demonstrate a possible new technique for determination of superconducting film homogeneity. We hope that these effects can be used in the electronics.