MICROWAVE MAGNETIC-ENVELOPE DARK SOLITONS IN YTTRIUM-IRON-GARNET THIN-FILMS

Dark solitons of magnetostatic surface waves in magnetic films have been observed for the first time. The experiments were conducted at 5.19 GHz on 7.2 mum single-crystal yttrium iron garnet films. The dark solitons were excited by 15 ns wide ''off'' pulses in a high power cw microwave signal applied to the film. The characteristic soliton narrowing effect in the output pulses was observed as the input power was increased above the 0.5-1 W threshold levels. The shape of the ''dark'' pulse agrees with the \tanh\ functional dependence predicted from theory. Direct measurements of the carrier signal showed a phase shift of close to 180-degrees at the center of the dark soliton, also in agreement with theory.