arXiv subjects

Enrick Olive

Publications and source records attributed to Enrick Olive.

2 recordsLinked to original sources

arXiv2020

Nutation Wave as a Platform for Ultrafast Spin Dynamics in Ferromagnets

At short time scales the inertia term becomes relevant for the magnetization dynamics of ferromagnets and leads to nutation for the magnetization vector. For the case of spatially extended magnetic systems, for instance Heisenberg spin chains with isotropic spin-exchange interaction, this leads to the appearance of a novel collective excitation, the "nutation wave", whose properties are elucidated by analytic arguments and numerical studies. The one--particle excitations can be identified as relativistic massive particles. These particles, the "nutatons", acquire their mass via the Brout-Englert-Higgs mechanism, through the interaction of the wave with an emergent topological gauge field. This spin excitation would appear as a peak in the spectrum of the scattering structure factor in inelastic neutron scattering experiments. The high frequency and speed of the nutation wave can open new paths for realizing ultrafast spin dynamics.

cond-mat.mes-hall↗

arXiv2016

The magnetic monopole and the separation between fast and slow magnetic degrees of freedom

The Landau-Lifshitz-Gilbert (LLG) equation that describes the dynamics of a macroscopic magnetic moment finds its limit of validity at very short times. The reason for this limit is well understood in terms of separation of the characteristic time scales between slow degrees of freedom (the magnetization) and fast degrees of freedom. The fast degrees of freedom are introduced as the variation of the angular momentum responsible for the inertia. In order to study the effect of the fast degrees of freedom on the precession, we calculate the geometric phase of the magnetization (i.e. the Hannay angle) and the corresponding magnetic monopole. In the case of the pure precession (the slow manifold), a simple expression of the magnetic monopole is given as a function of the slowness parameter, i.e. as a function of the ratio of the slow over the fast characteristic times.

cond-mat.mes-hall↗