Dynamical Dzyaloshinsky-Moriya Interaction in KCuF3

Authors :: Eremin, M. V.
Zakharov, D. V.
von Nidda, H. -A. Krug
Eremina, R. M.
Shuvaev, A.
Pimenov, A.
Ghigna, P.
Deisenhofer, J.
Loidl, A.
Publication Year :: 2008
Abstract: The spin dynamics of the prototypical quasi one-dimensional antiferromagnetic Heisenberg spin S=1/2 chain KCuF3 is investigated by electron spin resonance spectroscopy. Our analysis shows that the peculiarities of the spin dynamics require a new dynamical form of the antisymmetric anisotropic spin-spin interaction. This dynamical Dzyaloshinsky-Moriya interaction is related to strong oscillations of the bridging fuorine ions perpendicular to the crystallographic c axis. This new mechanism allows to resolve consistently the controversies in observation of the magnetic and structural properties of this orbitally ordered perovskite compound.<br />Comment: 4 pages, 3 figures