EDGE BARRIER MANIFESTATION IN THE NONLINEAR MICROWAVE RESPONSE OF THIN YBACUO FILMS

The initial cubic-law regime H-3 omega proportional to H-omega(3) in t he amplitude dependence of the third harmonic H-3 omega(H-omega) was f ound to change when the microwave field H-omega perpendicular to the s urface of the YBaCuO film reached the value H-omega. The observed dep endences H-omega proportional to R(i)(1/2)(T-c-T) on the film radius R(i) and on the temperature T close to the critical temperature T-c an d comparison of H-omega with the computed value of the field, in whic h the current density at the film edge reaches the critical value, mak e it possible to identify H-omega as the field that suppresses the ed ge surface barrier. (C) 1995 American Institute of Physics.