Static distortions and resistivity due to interstitials

Abstract

It has been suggested (1) that the electrical resitivity (ρ) of interstitial alloys is proportional to the mean-square static displacements 〈 μ s 2〉 caused by the interstitials and that Δ ρs Δ〈μ s 2〉 = Δ ρ thermal Δ〈μ 2〉 thermal . To test this relationship, oxygen and nitrogen in varying amounts have been dissolved in high-purity vanadium powders prepared by filing under purified Argon. The mean-square displacements were measured as a function of interstitial concentration by plotting the logarithm of the integrated X-ray intensity vs sin 2 θ λ 2 . For oxygen, Δ ρs Δ〈μ 2〉 s = 4.97(36) × 10 3 μΩ cm/ A ̊ 2 and for nitrogen, 4.91(14) × 10 3 μΩ cm/ A ̊ 2 , whereas from data in the literature Δ ρT Δ〈μ T 2〉 = 3.5–4.0 × 10 3 μΩ cm/ A ̊ 2 . Because the data was obtained for a range of interstitial concentrations (up to 5.5 at. % for oxygen and up to 8 % for nitrogen) a precise value for the peak depression for pure vanadium was obtained by extrapolation. From this value the Debye Temperature of Vanadium was calculated to be 352(3) K. The similarity in mean-square displacements of oxygen and nitrogen vs concentration suggests that both elements occupy the same type of interstitial sites in vanadium.