Spin-nematic interaction in the multiferroic compound Ba2CoGe2O7.
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.
Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Tokai, Ibaraki 319-1106, Japan.
M
M
Soda
Department of Physics, Shizuoka University, Shizuoka 422-8529, Japan.
M
M
Matsumoto
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.
M
M
Månsson
Materials and Life Science Division, J-PARC Center, Tokai, Ibaraki 319-1195, Japan.
S
S
Ohira-Kawamura
Materials and Life Science Division, J-PARC Center, Tokai, Ibaraki 319-1195, Japan.
K
K
Nakajima
Department of Materials Science and Technology, Niigata University, Niigata 950-2181, Japan.
R
R
Shiina
Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Tokai, Ibaraki 319-1106, Japan.
T
T
Masuda