NONRECIPROCAL PHASE-BEHAVIOR IN REFLECTION OF ELECTROMAGNETIC-WAVES FROM MAGNETIC-MATERIALS

Most experimental and theoretical treatments of reflection of electrom agnetic radiation from magnetic materials have concentrated on the int ensity of the reflected and transmitted waves. We point out that the b ehavior of the phase of these waves can be quite different from the in tensity, and that it can have direct experimental consequences. In par ticular, the reflected intensity from a magnetic material with low dam ping in the Voigt geometry is reciprocal, i.e., the intensity is the s ame when the reflected and incident waves are interchanged. In contras t; the phase of the reflected wave is strongly nonreciprocal. This non reciprocity in phase produces a nonreciprocal intensity in a structure where a dielectric film is placed on an antiferromagnet. We explore t he general properties of the phase and amplitude of reflected and tran smitted waves in a variety of geometries using the antiferromagnet FeF 2 as an example. General thermodynamic arguments are used to support s ome of the specific results. [S0163-1829(98)05026-7].