Ultrafast terahertz magnetometry.

Zhang W; Maldonado P; Jin Z; Seifert TS; Arabski J; Schmerber G; Beaurepaire E; Bonn M; Kampfrath T; Oppeneer PM; Turchinovich D

doi:10.1038/s41467-020-17935-6

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Journal article

Ultrafast terahertz magnetometry.

Zhang W Fakultät für Physik, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany.
Maldonado P Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden.
Jin Z Terahertz Technology Innovation Research Institute, University of Shanghai for Science and Technology, JunGong Road 516, 200093, Shanghai, China.
Seifert TS Department of Materials, ETH Zurich, Hönggerbergring 64, 8093, Zurich, Switzerland.
Arabski J Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (UMR 7504), 23 rue du Loess, BP 43, 67034, Strasbourg Cedex 2, France.
Schmerber G Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (UMR 7504), 23 rue du Loess, BP 43, 67034, Strasbourg Cedex 2, France.
Beaurepaire E Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (UMR 7504), 23 rue du Loess, BP 43, 67034, Strasbourg Cedex 2, France.
Bonn M Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
Kampfrath T Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
Oppeneer PM Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden.
Turchinovich D Fakultät für Physik, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany. dmtu@physik.uni-bielefeld.de.

2020-08-27

Published in:

Nature communications. - 2020

General Biochemistry, Genetics and Molecular Biology

English A material's magnetic state and its dynamics are of great fundamental research interest and are also at the core of a wide plethora of modern technologies. However, reliable access to magnetization dynamics in materials and devices on the technologically relevant ultrafast timescale, and under realistic device-operation conditions, remains a challenge. Here, we demonstrate a method of ultrafast terahertz (THz) magnetometry, which gives direct access to the (sub-)picosecond magnetization dynamics even in encapsulated materials or devices in a contact-free fashion, in a fully calibrated manner, and under ambient conditions. As a showcase for this powerful method, we measure the ultrafast magnetization dynamics in a laser-excited encapsulated iron film. Our measurements reveal and disentangle distinct contributions originating from (i) incoherent hot-magnon-driven magnetization quenching and (ii) coherent acoustically-driven modulation of the exchange interaction in iron, paving the way to technologies utilizing ultrafast heat-free control of magnetism. High sensitivity and relative ease of experimental arrangement highlight the promise of ultrafast THz magnetometry for both fundamental studies and the technological applications of magnetism.

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