RANDOM TELEGRAPH NOISE SPECTRA IN GRANULAR HIGH-T(C) FILMS

Random telegraph noise voltages developing across current biased granu lar high-T(c) films interact with the system of Abrikosov vortices pin ned inside the grains through random Lorentz forces caused by the flow of random currents in the film. Viscous relaxation of vortices oppose s random forces and leads to the attenuation of the low frequency part of the observed spectra of the voltage noise. The theoretical model h as been created and discussed. The predictions of the model have been verified experimentally by observations of a peak in the random noise spectra recorded for granular YBaCuO thin film strips immersed in a we ak magnetic field and biased with a dc current flow above the critical current. It has been found that the peak position and its changes wit h changing random telegraph switching rate are in a good agreement wit h the theoretical predictions.