Influence of columnar defects on magnetic relaxation of microwave nonlinearity in superconducting YBCO resonator devices

Intermodulation distortion (IMD) of microwave signals incident upon a superconducting YBa2Cu3O7 thin film sample on LaAlO3 substrate is shown to relax as the magnetization also relaxes, revealing signature fluxon decay in distortion. The contained microchannel columnar defects that was introduced using heavy ion beam irradiation. After exposure and then removal low strength static magnetic field, IMD relaxed due thermal activation fluxons over surface barrier. This process influenced second third order differently, visible differing functional form time temperature dependence relaxation function. presence test suppressed by pinning fluxons, notably with complete suppression at temperatures. Higher found same parity.