Spin-nematic interaction in the multiferroic compound Ba2CoGe2O7

M Soda; M Matsumoto; M Månsson; S Ohira-Kawamura; K Nakajima; R Shiina; T Masuda

doi:10.1103/PhysRevLett.112.127205

Spin-nematic interaction in the multiferroic compound Ba2CoGe2O7

Phys Rev Lett. 2014 Mar 28;112(12):127205. doi: 10.1103/PhysRevLett.112.127205. Epub 2014 Mar 26.

Authors

M Soda¹, M Matsumoto², M Månsson³, S Ohira-Kawamura⁴, K Nakajima⁴, R Shiina⁵, T Masuda¹

Affiliations

¹ Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Tokai, Ibaraki 319-1106, Japan.
² Department of Physics, Shizuoka University, Shizuoka 422-8529, Japan.
³ Laboratory for Quantum Magnetism (LQM), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland and Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
⁴ Materials and Life Science Division, J-PARC Center, Tokai, Ibaraki 319-1195, Japan.
⁵ Department of Materials Science and Technology, Niigata University, Niigata 950-2181, Japan.

PMID: 24724679
DOI: 10.1103/PhysRevLett.112.127205

Abstract

We demonstrate the existence of the spin-nematic interactions in an easy-plane type antiferromagnet Ba2CoGe2O7 by exploring the magnetic anisotropy and spin dynamics. The combination of neutron scattering and magnetic susceptibility measurements reveals that the origin of the in-plane anisotropy is an antiferro-type interaction of the spin-nematic operator. The relation between the nematic operator and the electric polarization in the ligand symmetry of this compound is presented. The introduction of the spin-nematic interaction is useful to understand the physics of spin and electric dipole in multiferroic compounds.