Single-crystalline BiMnO3 studied by temperature-dependent x-ray diffraction and Raman spectroscopy

Pierre Toulemonde (1) , Pierre Bordet (1) , Pierre Bouvier (2) , Jens Kreisel (3)

1 NEEL - MRS - Matériaux, Rayonnements, Structure
2 LMGP - Laboratoire des matériaux et du génie physique
3 Centre de Recherche Public - Gabriel Lippmann (LUXEMBOURG)

We report on the temperature dependence of the phonons and crystallographic parameters in BiMnO3 single crystals grown under high pressure and high temperature. The crystallographic structure of the sample was refined from room temperature to liquid helium temperature in the centrosymmetric C2/c space group, i.e., a group which does not allow ferroelectricity. In addition, the lattice dynamics was probed by Raman spectroscopy down to liquid nitrogen temperature, i.e., below the ferromagnetic transition at TC = 100 ± 2 K. Both crystallographic and Raman data indicate the absence of a structural phase transition at the ferromagnetic ordering or any other temperature. The Raman signature around TC shows a significant spin-phonon coupling for the high-frequency bands.

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

Pierre Toulemonde, Pierre Bordet, Pierre Bouvier, Jens Kreisel. Single-crystalline BiMnO3 studied by temperature-dependent x-ray diffraction and Raman spectroscopy. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2014, 89 (22), pp.224107. ⟨10.1103/PhysRevB.89.224107⟩. ⟨hal-01021920⟩