Ultrafast changes of magnetic anisotropy driven by laser-generated coherent and noncoherent phonons in metallic films

Kats, V.N. and Linnik, T.L. and Salasyuk, A.S. and Rushforth, A.W. and Wang, M. and Wadley, P. and Akimov, Andrey V. and Cavill, S.A. and Holy, V. and Kalashnikova, A.M. and Scherbakov, A.V. (2016) Ultrafast changes of magnetic anisotropy driven by laser-generated coherent and noncoherent phonons in metallic films. Physical Review B, 93 (21). 214422-1-214422-10. ISSN 2469-9969

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Abstract

Ultrafast optical excitation of a metal ferromagnetic film results in a modification of the magnetocrystalline anisotropy and induces the magnetization precession. We consider two main contributions to these processes: an effect of noncoherent phonons, which modifies the temperature dependent parameters of the magnetocrystalline anisotropy and coherent phonons in the form of a strain contributing via inverse magnetostriction. Contrary to earlier experiments with high-symmetry ferromagnetic structures, where these mechanisms could not be separated, we study the magnetization response to femtosecond optical pulses in the low-symmetry magnetostrictive galfenol film so that it is possible to separate the coherent and noncoherent phonon contributions. By choosing certain experimental geometry and external magnetic fields, we can distinguish the contribution from a specific mechanism. Theoretical analysis and numerical calculations are used to support the experimental observations and proposed model.

Item Type: Article
Schools/Departments: University of Nottingham UK Campus > Faculty of Science > School of Physics and Astronomy
Identification Number: https://doi.org/10.1103/PhysRevB.93.214422
Depositing User: Rushforth, Andrew
Date Deposited: 22 Sep 2016 14:44
Last Modified: 25 Sep 2016 04:26
URI: http://eprints.nottingham.ac.uk/id/eprint/37050

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