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Andreï KIRILYUK - Pays-Bas

Balance of angular momentum and magnetization switching in ferrimagnetic alloys and multilayers


Résumé :

Many peculiarities of magnetization dynamics are related to the fact that a certain amount of angular momentum is associated with magnetic moments. Here I would like to consider the mechanism responsible for the ultrafast heat-induced switching of the magnetization in ferrimagnetic alloys and multilayers. This switching is found to follow a counterintuitive pathway via a ferromagnetic state, which crucially depends on the angular momentum balance of the two opposite sublattices. It appeared that the transient state is due to two reasons : (i) considerably different demagnetization times of the RE and TM sublattices, and (ii) angular-momentum conservation and its transfer between the sublattices [1]. Thus, most interesting, this switching is fully due to the non-equilibrium behavior of the magnetization. Even more intriguing appears the evolution of this behavior from alloys to multilayers, where huge-amplitude precession accompanies the switchign process.

 

[1] A. Kirilyuk, A.V. Kimel, and Th. Rasing, “Laser-induced magnetization dynamics and reversal in ferrimagnetic alloys” Rep. Prog. Phys. 76, 026501 (2013).

 

Coordonnées :

Radboud University Nijmegen, Institute for Molecules and Materials,
Nijmegen, The Netherlands

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Andrei Kirilyuk