Spin-nematic interaction in the multiferroic compound BaCoGeO

Soda, Minoru*; Matsumoto, Masashige*; Mnsson, M.*; Kawamura, Seiko; Nakajima, Kenji; Shiina, Ryosuke*; Masuda, Takatsugu*

Physical Review Letters, 112(12), p.127205_1 - 127205_5, 2014/03

https://doi.org/10.1103/PhysRevLett.112.127205

We demonstrate the existence of the spin-nematic interactions in an easy-plane type antiferromagnet BaCoGeO 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 spinnematic interaction is useful to understand the physics of spin and electric dipole in multiferroic compounds.