Ultrafast magnetism as seen by x-rays

Ilie Radu, Kadir Vahaplar, Christian Stamm, Torsten Kachel, Niko Pontius, Florin Radu, Radu Abrudan, Hermann Dürr, Thomas Ostler, Joe Barker, Richard Evans, Roy Chantrell, Arata Tsukamoto, Akiyoshi Itoh, Andrei Kirilyuk, Theo Rasing, Alexey Kimel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

Revealing the ultimate speed limit at which magnetic order can be controlled, is a fundamental challenge of modern magnetism having far reaching implications for magnetic recording industry. Exchange interaction is the strongest force in magnetism, being responsible for ferromagnetic or antiferromagnetic spin order. How do spins react after being optically perturbed on an ultrashort timescales pertinent to the characteristic time of the exchange interaction? Here we demonstrate that femtosecond measurements of X-ray magnetic circular dichroism provide revolutionary new insights into the problem of ultrafast magnetism. In particular, we show that upon femtosecond optical excitation the ultrafast spin reversal of Gd(FeCo) - a material with antiferromagnetic coupling of spins - occurs via a transient ferromagnetic state. The latter one emerges due to different dynamics of Gd and Fe magnetic moments: Gd switches within 1.5 ps while it takes only 300 fs for Fe. Thus, by using a single fs laser pulse one can force the spin system to evolve via an energetically unfavorable way and temporary switch from an antiferromagnetic to ferromagnetic type of ordering. These observations supported by atomistic simulations, present a novel concept of manipulating magnetic order on different classes of magnetic materials on timescales of the exchange interaction.

Original languageEnglish
Title of host publicationUltrafast Phenomena and Nanophotonics XVI
DOIs
Publication statusPublished - 2012 Mar 23
EventUltrafast Phenomena and Nanophotonics XVI - San Francisco, CA, United States
Duration: 2012 Jan 222012 Jan 25

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume8260
ISSN (Print)0277-786X

Other

OtherUltrafast Phenomena and Nanophotonics XVI
Country/TerritoryUnited States
CitySan Francisco, CA
Period12/1/2212/1/25

Keywords

  • Exchange interaction
  • Ultrafast magnetization switching
  • X-ray Magnetic Circular Dichroism

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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