Magnetic structure analyses of multiferroics RMnO3 and RMn2O5

Magnetic structure of typical multiferroic materials RMnO3 and RMn2O5 (R:rare earth) has been investigated by neutron diffraction. Magnetic structure analysis using single crystal revealed that both the materials have a cycloidal magnetic structure, where ferroelectricity arises. Polarized neutron diffraction under electric field found the one-to-one correspondence between the direction of cycloidal rotation (spin chirality) and the direction of the electric polarization, evincing that the electric polarization is directly induced by the cycloidal magnetic order. (author)