Decay Free Microwave Magnetic Envelope Soliton Pulse Trains in Yttrium Iron Garnet Thin Films

Microwave magnetic envelope soliton pulse trains with no decay in amplitude have been obtained in magnetic films for the first time. The solitons were formed from magnetostatic spin waves with negative dispersion, or backward volume waves, propagated in a long and narrow $5.2\mu \mathrm{m}$ thick yttrium iron garnet film strip biased at 1096 Oe. An interrupted feedback technique was used to produce the soliton pulse trains from an initial 25 ns wide input pulse at a carrier frequency of 5.0 GHz. The train extended for over $40\mu \mathrm{s}$, 2 orders of magnitude longer than the single soliton lifetime. Measurements of the soliton width and phase profiles confirmed the soliton nature of the pulses over the entire train.