Conduction Electron Spin Resonance in Graphite Intercalation Compounds

Abstract

The conduction electron spin resonance in graphite intercalation compounds (GIC’s) has been theoretically studied. Expressions for Δg and 1⁄T₁ in stage-two GIC are obtained by using the Dresselhaus-Dresselhaus Hamiltonian. The Δg contributions originating from the two bands are found to cancel each other; this is consistent with the observed results. The calculated 1⁄T₁ is not only too small in the magnitude but of opposite sign in its temperature dependence, as compared with the experiments. Such a discrepancy can be removed by considering that inhomogeneous broadening caused by the exchange interaction between the two bands is motionally narrowed through the interband transition. Since spin flip process frequently occurs in the alkali s-electrons, spin-lattice relaxation in stage-one GIC is induced by the exchange interaction between the graphitic electrons and s-electrons.