Gadolinium-heavy rare earth alloys: preparation, metallographic study and extraordinary hall effect

Abstract

We present a study of the extraordinary Hall effect (EHE) in gadolinium containing rare earth impurities. The alloys were melted in an argon atmosphere (in sealed tantalum crucibles) or in a dynamic vacuum (in tantalum crucibles with a delayed leak). The Hall effect measurements show that the EHE induced by rare earth impurities in gadolinium is the sum of a skew scattering contribution proportional to the impurity resistivity Δρ 0 and a side jump term proportional to Δρ 0 2. The dependence of the EHE on the rare earth impurity indicates that it is mainly due to the spin-orbit coupling of the conduction band (rather than to orbital exchange) and we develop an appropriate model to interpret our results. By extending our model to the EHE of pure rare earth metals, we show that it arises mainly from side jump scattering and we present a quantitative interpretation of the EHE of pure gadolinium.