Magnonics of time-varying media: Giant amplification via phase-transition-driven temporal interfaces
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arXiv
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866917133039960064 |
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| author | Sobucki, Krzysztof Gruszecki, Pawel |
| author_facet | Sobucki, Krzysztof Gruszecki, Pawel |
| contents | Gilbert damping-the primary obstacle limiting spin-wave propagation in magnonic devices-can be transformed from an adversary into an asset. Here we demonstrate 175-fold spin-wave amplitude amplification in ultrathin films with perpendicular magnetic anisotropy at temporal interfaces associated with a field-driven transition between a uniform in-plane state and a stripe-domain state, exceeding existing parametric and spin-torque schemes (10-50-fold) without a continuous power supply. When the in-plane bias field is swept through a critical value in the presence of finite Gilbert damping, the spin-wave dispersion undergoes dramatic softening, and the eigenfrequency crosses zero and acquires a positive imaginary part that drives exponential growth. We identify this as a damping-induced instability operating near an exceptional point-a non-Hermitian degeneracy where, counterintuitively, increased Gilbert damping enhances amplification. This mechanism exploits ingredients specific to these magnetic films: the interplay of Gilbert damping, Dzyaloshinskii-Moriya-interaction-induced nonreciprocity, and field-driven phase transitions-a combination that, to our knowledge, has no direct counterpart in photonic or acoustic time-varying platforms. Our analytical framework provides explicit design rules, while micromagnetic simulations capture the full nonlinear dynamics, including stripe-domain formation. This work establishes temporal magnonics as a new paradigm for reconfigurable, lithography-free spin-wave control. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_07713 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Magnonics of time-varying media: Giant amplification via phase-transition-driven temporal interfaces Sobucki, Krzysztof Gruszecki, Pawel Mesoscale and Nanoscale Physics Applied Physics Gilbert damping-the primary obstacle limiting spin-wave propagation in magnonic devices-can be transformed from an adversary into an asset. Here we demonstrate 175-fold spin-wave amplitude amplification in ultrathin films with perpendicular magnetic anisotropy at temporal interfaces associated with a field-driven transition between a uniform in-plane state and a stripe-domain state, exceeding existing parametric and spin-torque schemes (10-50-fold) without a continuous power supply. When the in-plane bias field is swept through a critical value in the presence of finite Gilbert damping, the spin-wave dispersion undergoes dramatic softening, and the eigenfrequency crosses zero and acquires a positive imaginary part that drives exponential growth. We identify this as a damping-induced instability operating near an exceptional point-a non-Hermitian degeneracy where, counterintuitively, increased Gilbert damping enhances amplification. This mechanism exploits ingredients specific to these magnetic films: the interplay of Gilbert damping, Dzyaloshinskii-Moriya-interaction-induced nonreciprocity, and field-driven phase transitions-a combination that, to our knowledge, has no direct counterpart in photonic or acoustic time-varying platforms. Our analytical framework provides explicit design rules, while micromagnetic simulations capture the full nonlinear dynamics, including stripe-domain formation. This work establishes temporal magnonics as a new paradigm for reconfigurable, lithography-free spin-wave control. |
| title | Magnonics of time-varying media: Giant amplification via phase-transition-driven temporal interfaces |
| topic | Mesoscale and Nanoscale Physics Applied Physics |
| url | https://arxiv.org/abs/2512.07713 |