Crystalline field effect and magnetic ordering in the heavy fermion Kondo lattice Ce₆Pd₁₂In₅

Results of magnetic, specific heat, electric and thermal transport studies carried out on the novel hexagonal-type structure Ce₆Pd ₁₂In₅ compound, with a unique site for Ce, two sites for In and four sites for Pd are reported. The compound exhibits long-range order, probably of antiferromagnetic type, below ^TN=1.6K in spite of a moment reducing Kondo effect acting on the magnetic Ce³⁺ ions. A strong influence of magnetic field on the low temperature dependencies of susceptibility, specific heat and electrical resistivity is observed. The crystal-electric field effect, CEF, plays an influential role in the ground state of this compound. The CEF parameters have been estimated. Based upon the low-temperature specific heat we observe heavy fermion behavior with the electronic specific heat coefficient that is enhanced to the value of γ=132 mJ/Ce-mol K². In the electrical resistivity, a logarithmic character ρ4_f(T)∼-lnT is observed that arises from incoherent Kondo scattering. Towards low temperature this behavior evolves into Kondo lattice formation with a coherence temperature ^Tcoh≃ 5.3 K, before long-range order takes place. We propose that Ce ₆Pd₁₂In₅ presents a new case study for competing Kondo and magnetic ordering in a high-symmetry lattice, with CEF and magnetocrystalline anisotropy further impacting upon the cooperative magnetic behavior.