Ultrafast demagnetization dynamics of 4f antiferromagnets Show others and affiliations
2025 (English) In: Physical Review Materials, E-ISSN 2475-9953, Vol. 9, no 9, article id 094408Article in journal (Refereed) Published
Abstract [en]
We study the ultrafast demagnetization dynamics of 𝐿𝑛Rh2 Si2 (𝐿𝑛=Pr, Nd, Sm, Gd, Tb, Dy, Ho) antiferromagnets after excitation by a laser pulse, using a combination of density functional theory and atomistic spin and spin-lattice dynamics simulations. In the first step, we calculate the Heisenberg interactions using the magnetic force theorem and compare two approaches, where the 4𝑓 states of the rare earths are treated as frozen core states or as valence states with added correlation corrections. We find marked quantitative differences in terms of predicted Curie temperature for most of the systems, especially for those with a large orbital moment of the rare-earth cations. This can be attributed to the importance of indirect interactions of the 4𝑓 states through the Si states, which depends on the binding energy of the 4𝑓 states and coexists with Ruderman-Kittel-Kasuya-Yosida–type interactions mediated by the conduction states. However, qualitatively both approaches agree in terms of the predicted antiferromagnetic ordering at low temperature, which is in line with previous experiments. In the second step, the atomistic dynamics simulations are used in combination with a heat-conserving two-temperature model, which allows for the calculation of spin and electronic temperatures during the magnetization dynamics simulations. Our simulations demonstrate that despite quite different demagnetization times, magnetization dynamics of all studied 𝐿𝑛Rh2Si2 antiferromagnets exhibit similar two-step behavior, in particular the first fast drop followed by slower demagnetization. In addition, we observe that the demagnetization amplitude depends linearly on laser fluence, for low fluences, something that is also in agreement with experimental observations. We also investigate the impact of lattice dynamics on ultrafast demagnetization using coupled atomistic spin-lattice dynamics simulations and the heat-conserving three-temperature model, which confirm the linear dependence of magnetization on laser fluence. The microscopic mechanisms behind these behaviors are investigated in detail.
Place, publisher, year, edition, pages American Physical Society, 2025. Vol. 9, no 9, article id 094408
National Category
Condensed Matter Physics
Research subject Physics and Mathematics
Identifiers URN: urn:nbn:se:his:diva-25858 DOI: 10.1103/rjvq-qs9x ISI: 001578270000001 Scopus ID: 2-s2.0-105023295173 OAI: oai:DiVA.org:his-25858 DiVA, id: diva2:2001024
Funder Knut and Alice Wallenberg Foundation, 2018.0060 Knut and Alice Wallenberg Foundation, 2021.0246 Knut and Alice Wallenberg Foundation, 2022.0108 Swedish Research Council, 2019-03666 Swedish Research Council, 2023-04239 Swedish Research Council, 2022-06725 German Research Foundation (DFG), TRR 227 - 328545488
Note CC BY 4.0
Maryna Pankratova
This work was financially supported by the Knut and Alice Wallenberg Foundation through Grants No. 2018.0060, No. 2021.0246, and No. 2022.0108. O.E. and M.P. acknowledge support from the Wallenberg Initiative Materials Science for Sustainability (WISE) funded by the Knut and Alice Wallenberg Foundation (KAW). O.E. also acknowledges financial support from the Swedish Research Council (Vetenskapsrådet, VR), the European Research Council (854843-FASTCORR), and STandUP. M.P. acknowledge support from Olle Engkvist Foundation (Grant No. 218-0077) and from WISE-WASP joint call. O.E. and A.B. acknowledge eSSENCE for financial support. A.B. acknowledges the Carl Trygger Foundation (CTS) and Uppsala University’s AI4Research for financial support. D.T. acknowledges financial support from the Swedish Research Council (Vetenskapsrådet, VR) Grants No. 2019-03666 and No. 2023-04239. A.E. acknowledges the funding by the Fonds zur Förderung der Wissenschaftlichen Forschung (FWF) under Grant No. I 5384. L.R. and Y.W.W. acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the Transregio TRR 227 - 328545488 Ultrafast Spin Dynamics (Projects No. A10 and B07). This publication is part of the project NL-ECO: Netherlands Initiative for Energy-Efficient Computing (with project number NWA. 1389.20.140) of the NWA research programme Research Along Routes by Consortia, which is financed bythe Dutch Research Council (NWO). The computations were enabled by resources provided by the National Academic Infrastructure for Supercomputing in Sweden (NAISS) at the National Supercomputing Centre (NSC, Tetralith cluster) partially funded by the Swedish Research Council through Grant Agreement No. 2022-06725. The structural sketch in Fig. 2 was produced using the VESTA3 software [34].
2025-09-252025-09-252026-05-21 Bibliographically approved