Time evolution of a pumped molecular magnet-A time-resolved inelastic neutron scattering study.

Autor: Reeder TR; William H. Miller III Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218., Titum P; William H. Miller III Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218.; Research and Exploratory Development, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723., Kindervater J; William H. Miller III Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218., Stewart VJ; William H. Miller III Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218., Ye Q; National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899., Rodriguez-Rivera JA; National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899., Qiu Y; National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899., Maliszewskyj N; National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899., McQueen TM; William H. Miller III Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218.; Department of Chemistry, The Johns Hopkins University, Baltimore, MD 21218.; Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, MD 21218., Broholm CL; William H. Miller III Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218.; National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899.; Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, MD 21218.
Jazyk: angličtina
Zdroj: Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2025 Jan 07; Vol. 122 (1), pp. e2415300121. Date of Electronic Publication: 2025 Jan 02.
DOI: 10.1073/pnas.2415300121
Abstrakt: Introducing an experimental technique of time-resolved inelastic neutron scattering (TRINS), we explore the time-dependent effects of resonant pulsed microwaves on the molecular magnet Cr 8 F 8 Piv 16 . The octagonal rings of magnetic Cr 3+ atoms with antiferromagnetic interactions form a singlet ground state with a weakly split triplet of excitations at 0.8 meV. A 4.6 tesla field was applied to tune the splitting between two members of the triplet excited level [Formula: see text] to resonance with 105 GHz (0.434 meV) microwaves. The time-dependent occupations of the ground state [Formula: see text], lower lying levels [Formula: see text] and [Formula: see text], and higher energy states [Formula: see text] were extracted during and after 20 s long microwave pulses incident along the (101) direction of a Cr 8 F 8 Piv 16 crystal held at 1.9 K. At significantly elevated spin temperatures, we found underpopulation relative to thermal equilibrium of [Formula: see text] and spin-lattice thermalization time scales ranging from 1.6(2) s to 5.7(2) s depending on the power level. This contrasts with the relaxation time [Formula: see text]s inferred for [Formula: see text] from in situ Electron Spin Resonance measurements. By probing a broad range of excited states during intense microwave pumping, TRINS thus provides a first view of long lived excited states in a molecular antiferromagnet.
Competing Interests: Competing interests statement:The authors declare no competing interest.
Databáze: MEDLINE
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