Kondo lattice heavy fermion behavior in CeRh2Ga2

Abstract

The physical properties of an intermetallic compound CeRh2Ga2 have been investigated by magnetic susceptibility χ(T), isothermal magnetization M(H), heat capacity C_p(T), electrical resistivity ρ(T), thermal conductivity κ(T) and thermopower S(T) measurements. CeRh2Ga2 is found to crystallize with CaBe2Ge2-type primitive tetragonal structure (space group P4/nmm). No evidence of long range magnetic order is seen down to 1.8 K. The χ(T) data show paramagnetic behavior with an effective moment μ_eff ~ 2.5 μ_B/Ce indicating Ce^3+ valence state of Ce ions. The ρ(T) data exhibit Kondo lattice behavior with a metallic ground state. The low-T C_p(T) data yield an enhanced Sommerfeld coefficient γ= 130(2) mJ/mol K^2 characterizing CeRh2Ga2 as a moderate heavy fermion system. The high-T C_p(T) and ρ(T) show an anomaly near 255 K, reflecting a phase transition. The κ(T) suggests phonon dominated thermal transport with considerably higher values of Lorenz number L(T) compared to the theoretical Sommerfeld value L_0.

6 pages, 6 figures, 1 table, Accepted for publication in J. Phys.: Condens. Matter