Interference of spin-, charge- and orbital degrees of freedom in low-carrier rare earth compounds, investigated by NMR

Abstract

In rare earth compounds, the concentration of charge carriers is known to strongly influence the nature, and the charge carriers caused by valence fluctuations result in a complete suppression of the magnetic state, as typically observed for YbInCu 4 . The notable exception has been reported for the cubic (NaCl structure) Tm X and Yb X families with low carrier, that exhibits antiferro-magnetic (AFM) order at low temperatures. Among these families, TmTe and YbSb with degenerate low-lying multiplets have an additional transition of antiferro-quadrupolar (AFQ) orderings. To elucidate the interplay between the electronic transport and magnetic and/or orbital phenomena close to a semiconductor-to-metal transition, we have carried NMR measurements of 63Cu in YbInCu 4 , 125 Te in TmTe, and 121 , 123 Sb in YbSb down to 1.2 K and the implication of NMR findings is discussed in terms of the CEF splitting.