Driving Spin Excitations by Hydrostatic Pressure in ${\mathrm{BiFeO}}_{3}$

Driving Spin Excitations by Hydrostatic Pressure in ${BiFeO}_{3}$

J. Buhot, C. Toulouse, Y. Gallais, A. Sacuto, R. de Sousa, D. Wang, L. Bellaiche, M. Bibes, A. Barthélémy, A. Forget, D. Colson, M. Cazayous, and M-A. Measson

Phys. Rev. Lett. 115, 267204 – Published 23 December 2015

Abstract

Optical spectroscopy has been combined with computational and theoretical techniques to show how the spin dynamics in the model multiferroic ${BiFeO}_{3}$ responds to the application of hydrostatic pressure and its corresponding series of structural phase transitions from $R 3 c$ to the $P n m a$ phases. As pressure increases, multiple spin excitations associated with noncollinear cycloidal magnetism collapse into two excitations, which show jump discontinuities at some of the ensuing crystal phase transitions. The effective Hamiltonian approach provides information on the electrical polarization and structural changes of the oxygen octahedra through the successive structural phases. The extracted parameters are then used in a Ginzburg-Landau model to reproduce the evolution with pressure of the spin wave excitations observed at low energy, and we demonstrate that the structural phases and the magnetic anisotropy drive and control the spin excitations.

Received 31 July 2015

DOI:https://doi.org/10.1103/PhysRevLett.115.267204

Physics Subject Headings (PhySH)

Pressure effects Spin waves

Insulators Multiferroics Oxides

Approximation methods for many-body systems Raman spectroscopy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

J. Buhot^1,*, C. Toulouse¹, Y. Gallais¹, A. Sacuto¹, R. de Sousa², D. Wang³, L. Bellaiche⁴, M. Bibes⁵, A. Barthélémy⁵, A. Forget⁶, D. Colson⁶, M. Cazayous^1,†, and M-A. Measson^1,‡

¹Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet 75205 Paris Cedex 13, France
²Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada, V8W 2Y2
³Electronic Materials Research Laboratory–Key Laboratory of the Ministry of Education, and International Center for Dielectric Research, Xi’an Jiaotong University, Xi’an 710049, China
⁴Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
⁵Unité Mixte de Physique CNRS/Thales, 1 avenue Augustin Fresnel, Campus de l’Ecole Polytechnique, F-91767 Palaiseau, France et Université Paris-Sud, 91405 Orsay, France
⁶Service de Physique de l’Etat Condensé, CEA Saclay, IRAMIS, SPEC (CNRS URA 2464), F-91191 Gif sur Yvette, France

^*Present address: High Field Magnet Laboratory, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
^†Corresponding author. maximilien.cazayous@univ-paris-diderot.fr
^‡Corresponding author. marie-aude.measson@univ-paris-diderot.fr