The microwave power handling of an FIB-generated weak link in a YBCO film

We have measured the power-dependent microwave properties of a weak link in a YBa2Cu3O7-delta thin film formed by writing a line of damage using a focused ion beam. The measurement was made using a parallel plate resonator at 5.5 GHz with the weak link written across the width of one of the plates. The ion-induced damage was characterized using a TRIM computer simulation and the de properties of similar weak links were measured Using a 200 eV Si ion dose of 2 x 10(13) cm(-2), T-c of the damaged region was reduced by 5.5 K and the normal resistivity was doubled. Surprisingly, the microwave measurements did not show any Josephson junction characteristics. Rather, the ion-damaged region exhibited a greatly increased microwave resistivity that was constant as a function of microwave power up to rf fields of 20 mT at 21 K.