Low-energy quasi-one-dimensional spin dynamics in charge-ordered La2−xSrxNiO4

Abstract

The low-energy spin excitations of La${}_{2\ensuremath{-}x}$Sr${}_{x}$NiO${}_{4}$, $x=0.275$ and $1/3$, have been investigated by unpolarized- and polarized-inelastic neutron scattering from single crystals. A pattern of magnetic diffuse scattering is observed in both compositions and is consistent with quasi-one-dimensional AFM spin correlations along the charge stripes. Analysis of the energy line shape for $x=1/3$ indicates that the diffuse scattering is inelastic with a characteristic energy of $1.40\ifmmode\pm\else\textpm\fi{}0.07$ meV. There is no discernible difference between the diffuse scattering from $x=0.275$ and $x=1/3$, suggesting that it is an intrinsic property of the charge stripes.