Continuous control of local magnetic moment by applied electric field in multiferroics Ba2CoGe2O7.

Ba2CoGe2O7 exhibits a collinear-antiferromagnetic structure with the easy axis along 〈100〉 directions and an antiferroelectric order with the polarization axis along the [001] direction. By applying the electric field the magnetic moment rotates from 〈100〉 to [110] directions and, simultaneously, the antiferroelectric state changes to the ferroelectric state gradually. This magnetoelectric effect, i.e., continuous control of the local magnetic moment by the electric field, is quantitatively explained by the Hamiltonian including the dielectric energy. [ABSTRACT FROM AUTHOR]