Application of EBIV technique for investigation of electrophysical parameters of devices based on HTSC

Local investigations with 4 μm spatial resolution using EBIV-signal registration of YBCO microstripes were made with low-temperature scanning microscopy. These investigations, coupled with microwave measurements of YBCO films (near-field microscopy) and structural investigations (X-ray diffractometry, SEM), gave the correlation between half-widths of the temperature dependence of the third harmonic power maximum WTH, EBIV-signal curve WEBIV verage microcrystallite size. In order to explain such a dependence, the diphasic medium model considering the non-linear voltage-current characteristic of the superconductor was proposed. Calculations allow us to conclude that a threefold increase of microcrystallite size results in hundredfold reduction of the non-linearity coefficient of YBCO films and microwave devices based on these films