The behaviour of the paramagnetic ions in the single crystals of some similar salts of the iron group of elements I. Hydrated cupric salts

Abstract

The anisotropic behaviours of a series of similarly constituted salts of the Cu 2+ ion have been compared by accurate methods of observation developed in this laboratory. It is found that the principal magnetic axes of the crystal and the relative orientation of the Cu 2+ ion in the unit cell change in most cases, in a few cases abnormally, owing to the anisotropic thermal expansion of the lattice. The thermal magnetic anisotropy behaviour of the Cu 2+ ion in most of the salts may be well represented in the form K 1 - K ┴ . Because of the degeneracy of the spin levels (except for very small spin interaction effects) in Cu 2+ ion, C / T 2 obviously arises in our range of temperatures mainly from a temperature-dependence of the theoretical high-frequency and Curie terms. Abnormalities in the values of the A and B terms also point to the same conclusion. The predominant B term is different from salt to salt and very markedly so between the alkali double salts on the one hand and ammonium and thallium double salts on the other. The tetragonal level separation in different salts and its variation with temperature are discussed.