Magnetoelastic and magnetoelectric couplings across the antiferromagnetic transition in multiferroic BiFeO 3

Mariusz Lejman (1) , Charles Paillard (2) , Vincent Juvé (1) , Gwenäelle G. Vaudel (1) , Nicolas Guiblin (2) , Laurent Bellaiche (3) , Michel Viret (4) , Vitali Goussev (5) , Brahim Dkhil (2) , Pascal Ruello (1)

1 IMMM - Institut des Molécules et Matériaux du Mans
2 SPMS - Laboratoire Structures, Propriétés et Modélisation des solides
3 Institute for nanosciences and engineering and physics departement [University of Arkansas]
4 LNO - Laboratoire Nano-Magnétisme et Oxydes
5 LAUM - Laboratoire d'Acoustique de l'Université du Mans

Clear anomalies in the lattice thermal expansion (deviation from linear variation) and elastic properties (soft-ening of the sound velocity) at the antiferromagnetic-to-paramagnetic transition are observed in the prototypical multiferroic BiFeO 3 using a combination of picosecond acoustic pump-probe and high-temperature x-ray-diffraction experiments. Similar anomalies are also evidenced using second-principles calculations supporting our experimental findings. Those calculations, in addition to a simple Landau-like model we also developed, allow us to understand the elastic softening and lattice change at T N as a result of magnetostriction combined with electrostrictive and magnetoelectric couplings, which renormalize the elastic constants of the high-temperature reference phase when the critical T N temperature is reached.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Mariusz Lejman, Charles Paillard, Vincent Juvé, Gwenäelle G. Vaudel, Nicolas Guiblin, et al.. Magnetoelastic and magnetoelectric couplings across the antiferromagnetic transition in multiferroic BiFeO 3. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2019, 99 (10), ⟨10.1103/PhysRevB.99.104103⟩. ⟨hal-02108984⟩