Magnetic sound birefringence in the easy-axis antiferromagnet α-Fe2O3

Abstract The rotation of the polarization plane of the linearly polarized transverse sound propagating along the trigonal symmetry axis C 3 in hematite ( α -Fe 2 O 3 ) at the orientation phase transition is experimentally found. It is shown that this effect is due to the antiferromagnetic linear birefringence of sound below the Morin temperature.