The infra-red spectrum and crystal structure of gypsum

Open Access
Publisher Website
Google Scholar
Abstract
The possibility of magnetic resonance measurements on an impurity in an antiferromagnetic host lattice is discussed. The ion is subject to an internal field B$_{\text{int}}$; consisting of B$_{\text{dip}}$, the dipolar field generated by the antiferromagnetic moments of the host ions, that can be calculated, and an exchange field B$_{\text{E}}$. For a simple two sublattice antiferromagnet, two resonance frequencies should be observed; equations for their angular dependence are given, including the effect of hyperfine interaction. Impurity ions with Kramers doublets are discussed, together with ions with singlet ground states, for which enhanced nuclear resonance should be possible. A number of simple antiferromagnetic compounds of lanthanide (4f) ions that order at liquid helium temperatures are mentioned briefly, but for simplicity, the discussion is concentrated on GdVO$_{4}$ as the host lattice. A formula, based on the known exchange field in the host lattice, is deduced for its effect on the impurity ion.

This publication has 3 references indexed in Scilit: