Bulk properties of single crystals of the valence-unstable compound SmRh2Si2

Abstract

We present the crystal growth as well as the structural, chemical and physical chracterization of SmRh _2 Si _2 single crystals. Their ground state is antiferromagnetic, as indicated by the behaviour of the magnetic susceptibility and the specific heat at the second order phase transition observed at T _N = 64 K. The Sommerfeld coefficient is small and similar to that of LuRh _2 Si _2 with ${\gamma }_{0}\approx 7$ mJ/(molK ^2 ). Susceptibility measurements show no Curie-Weiss behaviour at high temperatures which is a consequence of the large Van-Vleck contribution of the excited multiplets of Sm ^3+ . Previous angle-resolved photoemission studies showed that at 10 K, the valence of the Sm ions is smaller than three at the surface as well as in the bulk, suggesting a possible Kondo screening of the Sm ^3+ ions. This could not be observed in our thermodynamic and transport measurements.

Keywords

• Sm compounds
• magnetism
• valence instability
• SmRh2Si2
• Van-Vleck