Surface nonlinear magneto-optical effects in rhombic antiferromagnetics

Based on the group theoretical analysis of the nonlinear surface electric susceptibility we propose a new magneto-optical effect that can be used to detect antiferromagnetism at surface and in thin films. With the use of irreducible representation technique for the crystal space groups the formulas for surface polarization on the second-harmonic induced by the incident electromagnetic wave were derived. The principle possibility of antiferromagnetic domain visualization in zero external magnetic field was shown.