Understanding neutron scattering data in YMn2O5: An effective spin Hamiltonian.

We construct an effective spin Hamiltonian for YMn2O5 through analysis of first-principles density-functional theory results. Using our first-principles-derived spin Hamiltonian we calculate the magnon dispersion of this compound and compare with the experimentally measured spectra probed using inelastic neutron scattering. Our first-principles-derived set of magnetic interaction parameters show the importance of the Mn1-Mn2 interaction along the b axis, which was ignored in the literature. We provide justification in favor of our first-principles-derived parameters. [ABSTRACT FROM AUTHOR]