Antiferromagnetism and Antiferromagnetic Resonance in a Rhombic Crystal atT=0

Abstract

Neél's phenomenological theory of antiferromagnetism at zero temperature has been worked out for a three-dimensional case. When the external magnetic field comes near to a certain hyperbola in the field space lying in the plane through the favored and the least favored direction of magnetization, an anomaly occurs. This anomaly consists of a rapid turn-over of the two opposed directions of magnetization into the direction perpendicular to the plane just mentioned. At much higher fields the two opposed directions of magnetization will deviate towards the field, and finally antiferromagnetism will go over into paramagnetic saturation.