A note on the magnetic intensities of powder neutron diffraction

Abstract

>General intensity formulas of powder neutron diffraction lines are given for magnetic structures with a single-spin-axis as a function of the spin direction with respect to the crystallographic axes. If we disregard the vector properties of spins and assign a positive or negative scattering amplitude to the magnetic atoms, these scalar scatterers constitute a configurational symmetry' of the magnetic structure. When this symmetry is tetragonal, rhombohedral or hexagonal, the powder intensities caanot provide more information than the angle between the spin direction and the unique axis of the structure. The ambiguity of spin directions in alpha Fe/sub 2/O/sub 3/, NiAs, and MnO type structures is discussed. (auth)