A method for indexing neutron powder diffraction peaks from spiral spin antiferromagnets

A method is presented for the indexing of satellite diffraction peaks which arise in neutron powder diffraction patterns of spiral spin antiferromagnets with general propagation vectors. It has been successfully used to determine the propagation vector in Cu_1/2Ga_1/2Cr₂S₄ and also to confirm the direction of the propagation vectors in other materials with known structures.