Семинар международной лаборатории физики конденсированного состояния: Mikhail Zhitomirsky, (CEA, Grenoble, France) "Multi-k states in frustrated spinel and kagome antiferromagnets"

Competing exchange interactions may produce various non-collinear spin structures. Still majority of such magnetic states are coplanar with non coplanar states presented by only a few known examples. We investigate the multi-k magnetic structures with commensurate propagation wave vectors that can appear in spinel and kagome materials. For the isotropic Heisenberg Hamiltonian we find that the triple-k configurations are the most stable states in zero field for both systems. With increasing magnetic field they universally transform into the double-k magnetic structures. We also study the effect of magnetic anisotropies on the equilibrium spin configurations and in particular demonstrate that the splitting of the transition in GeNi2O4 is naturally explained by the local easy-plane anisotropy.