Influence of Defect Scattering on Temperature Dependence of In-plane Resistivity of Graphite

Abstract

Temperature dependence of the in-plane resistivities (ρ_a) of several graphite specimens has been investigated between 4.2 K and 300 K. In the case of specimens less perfect than sigle crystal, gradient of the dependence curve becomes more gentle above 100 K, indicating that Matthiessen's rule is invalid. In order to explain the observations, an expression for ρ_a (T) including the relaxation time of defect scattering on the basis of Sugihara-Ono's formula is introduced; thereby experimental data have been satisfactorily reproduced.