Stabilization of a nonlinear magnonic bullet coexisting with a Bose-Einstein condensate in a rapidly cooled magnonic system driven by spin-orbit torque

Non-local magnon transconductance in extended magnetic insulating films.\\ Part I: spin diode effect

“…This would then suggest that the spinwaves propagate between the two metallic electrodes by tunnel effect, and the propagation length is the decay length of the evanescent spinwave outside the well. This promotes self-localization effect [91][92][93] as reported in the analysis of Fig. 7 of Ref.…”

“…This pushes the whole spectral range of low-lying spin fluctuations at the emitter below the magnons' band gap for outside the emitter. This prevents these magnons to reach the collector and further promotes selflocalization [91][92][93]. The later gets further amplified by temperature variation produced by Joule heating when large currents are circulated into the emitter.…”

Non-local magnon transconductance in extended magnetic insulating films.\\Part II: two-fluid behavior

“…This localization is the consequence of three combined effects that impinge principally on the low-energy magnons: i) STE favors principally an increase of the density at the bottom of the magnon manifold, which has zero group velocity ii) STE, as an interfacial process, couples efficiently to surface magnetostatic modes [44], which are magnons propagating parallel to the wires iii) the nonlinear frequency shift associated with the demagnetizing field [45] produces a band mismatch at high power between the region underneath the emitter and outside, which prevents the propagation of magnons (see part I [1]). The spatial localization could be induced either by the thermal profile of Joule heating [13] or by the self-digging bullet modes [18,46,47]. This rational affects mainly the magnons, whose wavelengths are shorter than the width of the Pt electrode.…”