The microwave power threshold for S-N transition of a thin HTSC film

Power-induced S-N switching of a thin HTSC film deposited onto a thermally stabilized dielectric substrate is studied theoretically. The absorption of microwave power in the film is calculated using a two-fluid model of a superconductor. The threshold character of the S-N transition related to the thermal nonlinearity of the film is analysed. The threshold microwave power P-p to switch the film is calculated. It is shown that the threshold power P-p is much less than that reported earlier. At P > P-p the S-N transition occurs by means of N-S interface propagation over the film. N-S interface propagation velocity v and energy of critical thermal perturbations E(c) initiating its propagation are estimated. The results obtained may be of importance in the study of S-N switching in superconducting MW devices.