Commensurate transverse helical ordering in the room-temperature magnetoelectric Co(2)Z hexaferrite

Abstract

Using single crystal neutron diffraction, we confirmed the existence of the commensurate transverse helical ordering in Ba0.52Sr2.48Co2Fe24O41 upon zero-field cooling, in which room-temperature magnetoelectric coupling has been previously observed. Its magnetic structure remained commensurate to the lattice under the external field perpendicular to the c axis. We also found the commensurate ordering to be directly responsible for the electric polarization, which is the common feature of many types of hexaferrites independently of their zero-field orderings.