Wavevector and spin-flop transitions in cubic FeGe

Recent neutron diffraction data showing unusual temperature and magnetic-field-induced magnetic reordering in the helical spin-density wave phase of cubic FeFe are analysed in terms of a Landau-type free energy previously used to study related phenomena in isostructural MnSi. The predicted magnetic phase diagrams (H-T) exhibit novel types of first-order and second-order wavevector and spin reorientation phase transitions.