Manipulation of a collinear metallic antiferromagnet with femtosecond optical pulses and external strain

V. Grigorev,1,2 M. Filianina,1,2 Y. Lytvynenko,1 S. Sobolev,1 A.R. Pokharel,1 A. Sapozhnik,3 A. Kleibert,4 S.Yu. Bodnar,5 P. Grigorev,6 M. Kläui,1,2 H-J. Elmers,1,2
M. Jourdan,1 and J. Demsar1,2

1Institute of Physics, Johannes Gutenberg University, Germany

2Graduate School of Excellence Materials Science in Mainz, Germany

3Laboratory for Ultrafast Microscopy and Electron Scattering, EPFL Lausanne, Switzerland

4Paul Scherrer Institut, Swiss Light Source, Switzerland

5Walter Schottky Institut and Physics Department, Technical University Munich, Germany 6Centre Interdisciplinaire de Nanoscience de Marseille, France

Optical control of magnetization in numerous ferro and ferrimagnets1–3 has been demonstrated in recent years. While the absence of stray fields, the insensitivity to external magnetic fields and ultra-fast dynamics make antiferromagnets promising candidates for active elements in spintronic devices, optical control has been limited to a few insulating antiferromagnets with specific spin configurations at cryogenic temperatures.4,5 Here, we demonstrate optical manipulation of the staggered magnetization in the metallic collinear antiferromagnet Mn2Au by combining tensile strain and excitation with femtosecond optical pulses at room temperature. By applying tensile strain along one of the two orthogonal in-plane easy axes and exciting the sample at room temperature by a train of intense femtosecond pulses, we are able to manipulate the direction of the Néel vector, resulting in a stable magnetically aligned state. The dependence of optically induced Néel vector alignment on excitation density and strain suggests the alignment is a result of induced depinning of 90° domain walls and their montion in the direction of the free-energy gradient, governed by the magneto-elastic energy. Such an approach may be applicable to a wider range of collinear antiferromagnets.

1. Kimel, A. et al. Nature 435, 655–657 (2005).
2. Khorsand, A. R. et al., Phys. Rev. Lett. 108, 127205 (2012).
3. Lambert, C.-H. et al., Science 345, 1337–1340 (2014).
4. Satoh, T., Iida, R., Higuchi, T., Fiebig, M. & Shimura, T. Nat. Photonics 9, 25–29 (2015).
5. Manz, S. et al., Nat. Photonics 10, 653–656 (2016).

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