Antiferromagnetism in the Kondo lattice compound Ce₂Pd₃Si₅

The antiferromagnetic ordering state of the Kondo lattice compound Ce₂Pd₃Si₅ is ascertained by measuring the magnetic susceptibility χ, electrical resistivity ρ, thermoelectric power S, and specific heat C. The system undergoes an antiferromagnetic transition through two steps at T_N1 = 8.0 K and T_N2 = 7.4 K. The ordering occurred at T_N1 might be incommensurate with the lattice, and followed by a change of magnetic structure from incommensurate to commensurate with the lattice at T_N2. The magnetic entropy reaches 0.8R In 2 at 8.0 K. Thermoelectric power shows two positive peaks, one around 150 K and the other at 1.3 K, and a negative peak at 12 K. The crystal electric-field splitting levels are estimated to be Δ₁=90±10 K and Δ₂=470±50 K above the ground state, respectively.