Domain structure in centroantisymmetric antiferromagnets

The domain structure of an antiferromagnet whose magnetic-symmetry group contains a center of antisymmetry is studied theoretically. The magnetoelectric effect and weak ferromagnetism are shown to coexist in a domain wall. It is established that when the inhomogeneous magnetic moment interacts with a sufficiently strong magnetic field H ‖ C3, a multidomain state with an odd number of 180° domain walls becomes energetically favorable. The critical field for the transition from a single-domain state to a multidomain state is found. It is shown that domain reversal occurs when the magnetic field H is reversed.