Odd magnetic dichroism of linearly polarized light in the antiferromagnet MnF2

The two-sublattice tetragonal antiferromagnetic crystal manganese fluoride is found to exhibit dichroism induced by a magnetic field H∥C4∥Z for linearly polarized light propagating along the tetragonal axis of the crystal also. The observed effect is odd with respect to the sign of the z projection of the field and the operation of reversing the directions of the sublattice magnetic moments of the antiferromagnet. The effect can be used for optical visualization of 180-degree (time-reversed) antiferromagnetic domains in MnF2.