Ultrafast demagnetization in bulk versus thin films: an ab initio study.
J Phys Condens Matter
; 29(22): 224001, 2017 Jun 07.
Article
em En
| MEDLINE
| ID: mdl-28441143
ABSTRACT
We report ab initio simulations of the quantum dynamics of electronic charge and spins when subjected to intense laser pulses. By performing these purely electron-dynamics calculations for a thin film and for the bulk of Ni, we conclude that formation of surfaces has a dramatic influence of amplifying the laser induced demagnetization. The reason for this amplification is enhanced spin-currents on the surface of the thin films. We show that the underlying physics of demagnetization for bulk is dominated by spin-flips induced by spin-orbit coupling. In the case of thin films, the dominant cause of demagnetization is a combination of the flow of spin-currents and spin-flips. Furthermore, a comparison of our results with experimental data shows that below â¼120 fs processes of demagnetization are entirely dominated by purely electronic processes followed by which dissipative effects like the Elliott-Yafet mechanism start to contribute significantly.
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Base de dados:
MEDLINE
Idioma:
En
Revista:
J Phys Condens Matter
Assunto da revista:
BIOFISICA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Alemanha