Relative orientation of the magnetic moments in modulated multiferroic CaMn7O12

The modulated magnetic ordering in the multiferroic manganite CaMn 7 O 12 has been studied by using the neutron powder diffraction technique. The relative orientation of the magnetic moments of Mn 4+ and Mn 3+ ions located in Mn3 sublattice at (0,0,1/2) and Mn2 sublattice at (1/2,0,1/2) is shown to be antiparallel, i.e. their relative orientation angle Φ = π . This result differs from that given by other authors who propose another relative orientation with a value of Φ = 0.84 ( 4 ) π . The relative orientation angle is an important parameter used in model studies based on effective hamiltonians.