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MA: Fachverband Magnetismus

MA 9: Altermagnets I

MA 9.1: Vortrag

Montag, 17. März 2025, 15:00–15:15, H20

Tuning the Octupolar Degrees of Freedom in the Altermagnetic Candidate MnF₂ by Strain and Magnetic Field — •Rahel Ohlendorf^1,2, Hilary M. L. Noad¹, Jörg Schmalian³, Elena Hassinger², Andrew P. Mackenzie^1,4, and Elena Gati¹ — ¹Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany — ²Technical University, Dresden, Germany — ³Karlsruhe Institute of Technology, Karlsruhe, Germany — ⁴University of St Andrews, UK

Altermagnetism can unambiguously be differentiated from the known ferro- and antiferromagnetic phases within the framework of spin-group symmetry [1]. In centrosymmetric altermagnets the ordered state can be described in terms of ferroically ordered magnetic octupoles [2]. The experimental conjugate field that is predicted to couple to this order parameter is a combination of strain and magnetic field. Consequently the application of strain and magnetic field should enable the exploration of the physics near the ferrooctupolar critical point, including its associated crossover lines.

We discuss experimental phase diagrams on the centrosymmetric altermagnetic candidate MnF₂ in magnetic field and strain, mapped out by means of elastocaloric measurements and compare our results to theoretical predictions based on a Landau free energy [3].

[1]L. Smejkal et al., Phys. Rev. X 12, 031042 (2022)

[2]S. Bhowal et al., Phys. Rev. X 14, 011019 (2024)

[3]P. McClarty et al., Phys. Rev Lett. 132, 176702 (2024)

*Work is supported by the DFG through TRR288 (Elasto-Q-Mat).

Keywords: Altermagnets; Strain; MnF$_2$; Elastocalorics; Octupolar Order