Hyperfine Structure of the Paremagnetic Resonance Spectrum of divalent Cobalt: Theory

Abstract

THE magnetic properties of cobalt salts have been studied theoretically by Schlapp and Penney¹ under the assumption that there is one ion in the unit cell. To account for the anisotropy of the susceptibility, with three different principal values, they had to assume that the cobalt ion was acted upon by a field of predominantly cubic symmetry on which was superposed a field of lower (rhombic) symmetry, but were not able to draw any definite conclusions. The discovery by Bleaney and Ingram that in cobalt ammonium sulphate, with two ions in the unit cell, each ion has completely axial symmetry, within the experimental error, makes it possible to draw more detailed conclusions from their general theory.