Coherent and incoherent ultrafast magnetization dynamics in 3d ferromagnets driven by extreme terahertz fields

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F18%3A10380452" target="_blank" >RIV/00216208:11320/18:10380452 - isvavai.cz</a>
Result on the web
<a href="https://doi.org/10.1103/PhysRevB.98.014405" target="_blank" >https://doi.org/10.1103/PhysRevB.98.014405</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevB.98.014405" target="_blank" >10.1103/PhysRevB.98.014405</a>

Result language
angličtina
Original language name
Coherent and incoherent ultrafast magnetization dynamics in 3d ferromagnets driven by extreme terahertz fields
Original language description
Ultrafast spin dynamics in magnetic materials is generally associated with ultrafast heating of the electronic system by a near infrared femtosecond laser pulse, thus offering only an indirect and nonselective access to the spin order. Here we explore spin dynamics in ferromagnets by means of extremely intense THz pulses, as at these low frequencies the magnetic field provides a direct and selective route to coherently control the magnetization. We find that, at low fields, the observed off-resonantly excited spin precession is phase locked to the THz magnetic field. At extreme THz fields, the coherent spin dynamics become convoluted with an ultrafast incoherent magnetic quenching due to the absorbed energy. This demagnetization takes place upon a single shot exposure. The magnetic properties are found to be permanently modified above a THz pump fluence of approximate to 100 mJ/cm(2). We conclude that magnetization switching cannot be reached. Our atomistic spin-dynamics simulations excellently explain the measured magnetization response. We find that demagnetization driven by THz laser-field coupling to electron charges occurs, suggesting nonconducting materials for achieving coherent THz-magnetization reversal.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Project
<a href="/en/project/GA18-07172S" target="_blank" >GA18-07172S: Topical problems in theory of manipulation of spin polarization in bulk and layered systems</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2018
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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