Far-Infrared Magnetic Resonance in CoF2, NiF2, KNiF3, and YbIG

Abstract

The far-infrared transmission spectra of a variety of magnetic insulators have been measured using the techniques of Fourier-transformation interferometry. Antiferromagnetic resonance has been observed for the first time in CoF2, NiF2, and KNiF3, and the ferrimagnetic resonance in YbIG has been found near 0°K. The temperature dependences of these resonances have been measured and, in the case of the iron-group fluorides, the results are compared with the Zener theory for the temperature dependence of the anisotropy energy. Resonances previously found by other investigators in YbIG, MnF2, MnO, and NiO have been observed with (in most cases) improved precision.