Ferroelectric and antiferromagnetic domain wall

It has been experimentally confirmed that the ferroelectric (FEL) and anti ferro magnetic (AFM) order-parameter in hexagonal YMnO3 are coupled at the FEL domain boundary. A microscopic model for this clamping of the two order-parameters is proposed. The clamping can be understood as due to the change of exchange integrals induced by the spin-orbit interaction and low symmetry field within the FEL domain boundary and due to spin anisotropy energy which depends on the sign of FEL polarization.