Effect of annealing on the electrical resistivity of Kondo lattice CeRh₂Ga₂

Abstract

CeRh2Ga2, which crystallizes in CaBe2Ge2-type primitive tetragonal structure (space group P4/nmm), is known to exhibit Kondo lattice heavy fermion behavior and is proposed to be a potential candidate for Weyl-Kondo semimetal phase. Here we examine the effect of annealing particularly on the electrical resistivity of polycrystalline CeRh2Ga2. A comparative study of the powder x-ray diffraction (XRD), magnetic susceptibility χ(T), heat capacity Cp(T) and electrical resistivity ρ(T) data of both as-grown and annealed arc-melted CeRh2Ga2 samples are presented. The XRD patterns of both as-grown and annealed samples look similar. No marked effect of annealing could be clearly seen in the temperature dependences of χ and Cp data. However, the effect of annealing is clearly manifested in the T dependence of ρ, particlularly at low temperatures. At low-T the ρ(T) data of as-grown CeRh2Ga2 follow a T2 temperature dependence (Fermi-liquid feature), whereas the ρ(T) data of annealed CeRh2Ga2 exhibit an upturn (semimetal-like feature).