Mark M. Scott

Self-generation of bright microwave magnetic envelope soliton trains in ferrite films through frequency filtering

Resonant ring feedback with frequency filtering has been used for the self-generation of bright soliton trains. The solitons were produced from magnetostatic backward volume spin waves propagated in an in-plane magnetized magnetic film delay line as part of the resonant ring structure. The amplitude and phase time profiles, together with the power spectra of the self-generated pulses, confirm their bright soliton nature.

Nonlinear damping of high-power magnetostatic waves in yttrium–iron–garnet films

The nonlinear decay of continuous-wave magnetostatic surface wave and backward volume wave signals has been measured for propagation in a narrow 6.9 μm thick yttrium–iron–garnet film strip, with excitation frequencies and wave numbers between 5470 and 5630 MHz and 47 and 216 rad/cm, respectively. The results show: (1) that the onset of nonlinear damping is a threshold effect, and (2) that a nonlinear decay model with two damping terms, one linear and one quadratic in the wave power, are needed to model the measured response.

Spatial recurrence for nonlinear magnetostatic wave excitations

Spatial recurrence for nonlinear magnetic excitations has been observed. The recurrence was produced from the induced modulational instability of two input magnetostatic backward volume waves in a thin yttrium iron garnet film. The nominal frequency, frequency separation, and wave number were 5.5 GHz, 8 MHz, and 100 rad/cm, respectively. The spatial recurrence of the temporal wave form included frequency doubling and cnoidal profiles. A superposition of modes based on the observed Fourier makeup of the signals and calculated nonlinear phase shifts gave a response which matched the data.

Theoretical analysis of nonlinear pulse propagation in ferrite-dielectric-metal structures based on the nonlinear Schrödinger equation with higher order terms

An analysis of nonlinear magnetostatic surface wave pulse propagation in planar ferrite-dielectric-metal (FDM) structures has been performed. The analysis was based on numerical solutions to the higher-order nonlinear Schrodinger (HONLS) equation, with third-order (D3) and nonlinear (Q) dispersion terms taken into account. The analysis focuses on (1) the crossover dispersion region for FDM structures and the point in wave-number k where the second-order dispersion parameter D2 is a positive maximum, the Lighthill criterion for envelope soliton propagation is satisfied, and D3 is close to zero, and (2) the end points of this crossover region where D2 is zero. All operational HONLS equation parameters were evaluated from analytical dispersion expressions for the FDM structure and for magnetic field and structure parameters which match experiments. For (1), the pulse results indicate nondispersive propagation consistent with envelope solitons. The only effect of the Q term is to decrease slightly the propaga...

Suppression of microwave magnetic envelope solitons by continuous wave magnetostatic wave signals

The influence of continuous wave (cw) magnetostatic wave signals on microwave magnetic envelope soliton pulse formation and propagation in magnetic films has been examined. Pulsed and cw microwave signals were applied to the input of a single crystal yttrium–iron–garnet film magnetostatic wave delay line. The nominal operating frequency was 4.8 GHz. The pulse signals served to form solitons with no cw power present. Under suitable conditions, the cw signal served to inhibit or eliminate the soliton formation and propagation. The suppression effect was measured as a function of the cw signal frequency and power. The suppression is maximized when the cw signal frequency coincides with the pulse carrier frequency. At this frequency, an input cw power of 80 mW is sufficient to suppress completely a soliton pulse formed from a 10 ns wide, 500 mW peak power input pulse.

Generation of bright and dark envelope solitons from magnetostatic spin waves with attractive nonlinearity

In this paper, reports the first data on the generation of both bright and dark soliton trains in a medium with attractive nonlinearity. The success of the modified NLS equation model with nonlinear damping in matching the computed wave forms to the data indicates that, for cw excitation, the formation of nonlinear wave trains involves more than the competition between nonlinearity and dispersion. The match shows that nonlinear damping plays a crucial role in this process.

Recurrence phenomenon for microwave solitons in ferrite films

Summary form only given. Recurrence is a fundamental effect in nonlinear wave dynamics. The effect consists of a spatial recurrence of the temporal wave form for nonlinear excitations. Even though nonlinear dispersive systems have been studied extensively, recurrence has been observed in only a few systems. Recurrence has never been observed in any solid state system or for envelope solitons. In this work, a unique time and space resolved microwave probe system was used to observe recurrence for the first time for microwave magnetic envelope solitons in thin ferrite films.