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

Abstract

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 mm 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 ms, 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.

Spatial evolution of multipeaked microwave magnetic envelope solitons in yttrium iron garnet thin films

“…2 and 3 mirror and extend previous results for single peaked solitons. [3][4][5][6] These studies have shown that, when there is appropriate compensation between the dispersion and the nonlinear response, one can form a robust and non-dispersive bright MME soliton with a CP profile across the peak. Constant phase, therefore, provides a simple unambiguous criterion for bright MME soliton formation.…”

“…More specifically, Ref. 3 and later papers [4][5][6] show that single MME soliton pulses have a constant phase (CP) profile across the center part of the pulse. It is expected that multipeaked soliton (MPS) entities should also have peaks with a CP character.…”

Self-Generation of Microwave Magnetic Envelope Soliton Trains in Yttrium Iron Garnet Thin Films

“…(1) in [10] ]. For the experimental parameters, one obtains a theoretical soliton pulse width at half amplitude of 19.7 ns, which is in good agreement with the measured width of 20 ns.…”

“…Based on the nonlinear Schrödinger equation model (see, e.g., [3]), f 0 is equal to u 0 y g p jN͞Dj͞p, where u 0 is the signal amplitude. For D 520 cm 2 ͞rad s, N 29.9 3 10 9 rad͞s, and u 0 0.014, determined in the same way as in [10], f 0 is about 43 MHz. From theory, the maximum frequency width for the modulational instability zone is equal to 2f 0 or 86 MHz.…”

“…Most soliton experiments to date, however, have involved the application of input pulse signals and the observation of the soliton pulses which evolve as a result of these inputs. Many such experiments have been done for microwave magnetic envelope (MME) solitons in magnetic films of yttrium iron garnet (YIG) (see, e.g., [4][5][6][7][8][9][10][11] and literature therein). In all of these experiments, externally applied microwave pulses were used to produce the solitons.…”