Effect of annealing on the electrical resistivity of Kondo lattice CeRh₂Ga₂

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 C _p(T) and electrical resistivity ρ(T) data of both as-arc-melted and annealed CeRh₂Ga₂ samples are presented. The XRD patterns of both as-arc-melted and annealed samples look similar. No marked effect of annealing could be clearly seen in the temperature dependences of χ and C _p 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-arc-melted CeRh₂Ga₂ follow a T ² temperature dependence (Fermi-liquid feature), whereas the ρ(T) data of annealed CeRh₂Ga₂ exhibit an upturn (semimetal-like feature).