Enhanced electrical resistivity before Néel order in the metals, RCuAs${}_2$ (R= Sm, Gd, Tb and Dy

Abstract

We report an unusual temperature (T) dependent electrical resistivity($\ddot{I}$) behavior in a class of ternary intermetallic compounds of the type RCuAs${}_2$ (R= Rare-earths). For some rare-earths (Sm, Gd, Tb and Dy) with negligible 4f-hybridization, there is a pronounced minimum in $\ddot{I}$(T) far above respective Néel temperatures (T${}_N$). However, for the rare-earths which are more prone to exhibit such a $\ddot{I}$(T) minimum due to 4f-covalent mixing and the Kondo effect, this minimum is depressed. These findings, difficult to explain within the hither-to-known concepts, present an interesting scenario in magnetism.

Physical Review Letters (accepted for publication)