Electron spin resonance studies of doped rutile

Abstract

The Electron Spin Resonance Spectra at 9 GHz of iron doped rutile in both powder and single crystal form has been obtained at a variety of temperatures. The single crystal results have confirmed previous data; the Fe(^3+) ion enters the lattice substitutionally for the Ti(^4+) ion and the spectrum exhibits a pronounced anisotropy. The powders exhibited a variety of features not all of which were due to iron. The iron lines were identified both from the single crystals data and experimentally by comparing samples containing varying amounts of iron at several temperatures. An approach to calculate the powder spectra from the Spin Hamiltonian was examined and discarded in faviour of a faster, approximate, method. The latter assumed that the observed lines could be explained in terms of two separate transitions each with an effective spin of S = ½. Using an analytical formula for the overall powder line shape gave rather poor results but a program based on calculating the lineshape numerically using the g(^-1) factor of Oasa and Vanngard gave good results. This program can be used to simulate the spectra of other ions provided their behaviour can be approximated by transitions of spin ½.