Spin dynamics in the distorted triangular lattice antiferromagnet α−SrCr2O4
AbstractThe spin dynamics in the distorted triangular lattice antiferromagnet α−SrCr2O4 has been investigated by inelastic neutron scattering on a single crystal. The spin wave dispersion has been mapped out in the (0kl) and (hk0) planes, and modeled by spin wave calculations, in order to determine the intraplane and interplane exchange couplings. Comparison with α−CaCr2O4 shows that, despite the smaller lattice distortion of α−SrCr2O4, the deviation from a perfect triangular lattice still affects the spin dynamics of the Sr compound, with a soft mode, similar to the one observed in the Ca counterpart, being observed in (020). Although α−SrCr2O4 is further away from a magnetic phase boundary than its Ca counterpart, its dynamic magnetic properties still show intriguing features, which are discussed as quantum fluctuations arising from a two-magnon continuum.