Anton V. Velichko

Nonlinear microwave properties of high Tc thin films

This review presents an overview of the recent developments and achievements in the field of nonlinear microwave physics and applications of high temperature superconducting (HTS) thin films. It touches upon such issues as power-dependent surface impedance Zs, harmonic generation and intermodulation distortion. Various possible sources of the nonlinearity including grain boundaries, patterning, impurity doping, oxygen content and microwave heating are analysed and surveyed. Correlative studies of microstructural, microwave and other electromagnetic properties, as well as techniques of artificial modification of HTS films with the aim to improve their microwave performance, are reviewed. Possible perspectives for near future development of the nonlinear microwave science and application of HTS films are also discussed.

Unusual features in the nonlinear microwave surface impedance of Y-Ba-Cu-O thin films

Striking features have been found in the nonlinear microwave (8.0 GHz) surface impedance

Origin of the deviation of intermodulation distortion in high-Tc thin films from the classical 3:1 scaling

{Z}_{s}{=R}_{s}+j\ensuremath{\cdot}{X}_{s}

Highly-mismatched InAs/InSe heterojunction diodes

of high-quality YBaCuO thin films with comparable low power characteristics

Non-linear microwave surface impedance of epitaxial HTS thin films in low DC magnetic fields

[{R}_{\mathrm{res}}\ensuremath{\sim}35\char21{}60\ensuremath{\mu}\ensuremath{\Omega}

Temperature and magnetic field effects on microwave intermodulation in YBCO films

and

Microwave intermodulation distortion measurements in unpatterned and patterned YBCO thin films

{\ensuremath{\lambda}}_{L}(15\mathrm{K})\ensuremath{\sim}130\char21{}260\mathrm{nm}].

Effects of residual surface resistance on the microwave properties of YBCO thin films

The surface resistance

H-tailored surface conductivity in narrow band gap In(AsN)

{R}_{s}

Anomalous features in surface impedance of Y-Ba-Cu-O thin films: dependence on frequency, RF and DC fields

is found to increase, decrease, or remain independent of the microwave field