Calculation of electric field gradient in transitional and nontransitional dilute cubic alloys

Abstract

The electric field gradient (EFG) due to transitional and nontransitional impurities in fcc metals has been studied. Valence effect EFG has been calculated using parameter free dielectric screening theory which takes into account the s-, p- and d-character of host and impurity atoms. Size effect EFG has been calculated in elastic continuum model treating the ions in the screened point-ion model. Calculations of the EFG are performed for a number of Cu and Al alloys with nontransition metal impurities and for Al alloys with transition metal impurities. The calculated results agree reasonably with the experimental values and thus point out the importance of exact inclusion of pre-asymptotic contribution to the valence effect. The inadequacy of the elastic continuum model at least at the first nearest neighbor is emphasized. The dielectric screening approach is found to work reasonably well in both the transitional and nontransitional dilute metallic alloys.