An EPR Study of the Pyrites Co(x)Fe(1-X)S2, Ni(x)Fe(1-x)S2, and Co(x)Ni(y) Fe(1-x-y)S2

摘要

The paper reports on an EPR study of the pyrite solid solutions CoxFe1-xS2, and CoxNiyFe1-x-yS2. The single-ion spectrum for dilute Ni2+ in a pyrite structure was fitted to a spin Hamiltonian. The single-ion spectrum for Co2+ in FeS2 showed evidence of dynamic Jahn-Teller activity, with a broad, isotropic line. At metallic concentrations, FeS2:Co displayed the classically asymmetric, isotropic line of a conduction electron but with an unusually high g-value indicating the partial ionic character of narrow band electrons. The system FeS2:Ni:Co displayed both the broad lines characteristic of the itinerant Cobalt eg electrons and the localized Ni2+ spectrum. The peculiar Ni2+ lineshapes resulting from exchange effects with the itinerant electrons are analyzed on the basis of existing s-d interaction theory. (Author Modified Abstract)