Anatomy of inertial magnons in ferromagnets

Lomonosov, Alexey M.; Temnov, Vasily V.; Wegrowe, Jean-Eric

doi:10.48550/arxiv.2105.07376

Cited by 3 publications

(3 citation statements)

References 36 publications

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“…Theoretically, the spin nutation has recently been extensively discussed for one-sublattice ferromagnets [25,36,[40][41][42][43][44]. The nutation resonance has also been observed in experiments, however for two-sublattice ferromagnets [37].…”

Section: Introductionmentioning

confidence: 99%

Influence of intersublattice coupling on the terahertz nutation spin dynamics in antiferromagnets

Mondal

Oppeneer

2021

Phys. Rev. B

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Spin-nutation resonance has been well-explored in one-sublattice ferromagnets. Here, we investigate the spin nutation in two-sublattice antiferromagnets as well as, for comparison, ferrimagnets with inter-and intra-sublattice nutation coupling. In particular, we derive the susceptibility of the two-sublattice magnetic system in response to an applied external magnetic field. To this end, the antiferromagnetic and ferrimagnetic (sub-THz) precession and THz nutation resonance frequencies are calculated. Our results show that the precession resonance frequencies and effective damping decrease with intra-sublattice nutation coupling, while they increase with inter -sublattice nutation in an antiferromagnet. However, we find that the THz nutation resonance frequencies decrease with both the intra and inter-sublattice nutation couplings. For ferrimagnets, conversely, we calculate two nutation modes with distinct frequencies, unlike antiferromagnets. The exchange-like precession resonance frequency of ferrimagnets decreases with intra-sublattice nutation coupling and increases with inter-sublattice nutation coupling, like antiferromagnets, but the ferromagnetic-like precession frequency of ferrimagnets is practically invariant to the intra and inter-sublattice nutation couplings.

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Section: Introductionmentioning

confidence: 99%

Influence of intersublattice coupling on the terahertz nutation spin dynamics in antiferromagnets

Mondal

Oppeneer

2021

Phys. Rev. B

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“…The realization of such short and intense magnetic fields have been suggested recently designing magnetic-field enhancing metamaterials 32 , by the use of vector laser beams 33 or thanks to ultrafast electronic switches 34 . Finally, we anticipate that our findings will be relevant to much of the recent works in the magnetism community aimed at the understanding of inertial spin dynamics [35][36][37][38][39][40][41][42][43][44][45][46][47][48] . defined by a set of three unit vectors {e r , e θ , e φ }.…”

Section: Discussionmentioning

confidence: 99%

Magnetization switching in the inertial regime

Neeraj,

Pancaldi,

Scalera

et al. 2021

Preprint

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We have numerically solved the Landau-Lifshitz-Gilbert (LLG) equation in its standard and inertial forms to study the magnetization switching dynamics in a 3d thin film ferromagnet. The dynamics is triggered by ultrashort magnetic field pulses of varying width and amplitude in the picosecond and Tesla range. We have compared the solutions of the two equations in terms of switching characteristic, speed and energy analysis. Both equations return qualitatively similar switching dynamics, characterized by regions of slower precessional behavior and faster ballistic motion. In case of inertial dynamics, ballistic switching is found in a 25% wider region in the parameter space given by the magnetic field amplitude and width. The energy analysis of the dynamics is qualitatively different for the standard and inertial LLG equations. In the latter case, an extra energy channel, interpreted as the kinetic energy of the system, is available. Such extra channel is responsible for a resonant energy absorption at THz frequencies, consistent with the occurence of spin nutation.

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“…The experimental confirmation has been achieved only recently and detected nutation dynamics in the ∼ 1 THz range [24]. Despite this novel experimental evidence, and the significant theoretical progress to understand the microscopic origin of inertia [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44], a complete picture of how different material parameters affect the nutation dynamics is still missing. * stefano.bonetti@fysik.su.se…”

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confidence: 99%

Inertial spin dynamics in epitaxial cobalt films

Unikandanunni¹,

Medapalli²,

Asa³

et al. 2021

Preprint

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We investigate the spin dynamics driven by terahertz magnetic fields in epitaxial thin films of cobalt in its three crystalline phases. The terahertz magnetic field generates a torque on the magnetization which causes it to precess for about 1 ps, with a sub-picosecond temporal lag from the driving force. Then, the magnetization undergoes natural damped THz oscillations at a frequency characteristic of the crystalline phase. We describe the experimental observations solving the inertial Landau-Lifshitz-Gilbert equation. Using the results from the relativistic theory of magnetic inertia, we find that the angular momentum relaxation time η is the only material parameter needed to describe all the experimental evidence. Our experiments suggest a proportionality between η and the strength of the magneto-crystalline anisotropy.

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Anatomy of inertial magnons in ferromagnets

Cited by 3 publications

References 36 publications

Influence of intersublattice coupling on the terahertz nutation spin dynamics in antiferromagnets

Influence of intersublattice coupling on the terahertz nutation spin dynamics in antiferromagnets

Magnetization switching in the inertial regime

Inertial spin dynamics in epitaxial cobalt films

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