Heavy-Fermion Compound of the Ternary Phosphide Ce2Pt8P with a Non-Centrosymmetric Structure

The low-temperature properties of Ce2Pt8P are studied by magnetic susceptibility chi(T), electrical resistivity rho(T), and specific heat C(T) measurements. The crystal structure is considered to be analogs of the CePt3Si-type structure. From the magnetic susceptibility chi(T), the effective paramagnetic moment mu(eff) is estimated to be 2.30 mu(B)/Ce, suggesting that the valence state of Ce ions is expected to be close to trivalent (Ce3+). The paramagnetic Curie-Weiss temperature theta cw is determined to be 12 K. The electrical resistivity rho(T) shows -ln T dependence with a small slope from 10 to 3K, which indicates a weak Kondo anomaly. The specific heat exhibits a lambda-type anomaly at around T* = 1.0 K, while the magnetic entropy at T* is reduced to 80% of R ln 2. The linear coefficient of specific heat is determined to be 145 mJ=(mol-Ce.K-2). From several measurements, Ce2Pt8P can be classified as a moderate heavy-fermion compound. The ground state is far from the quantum-critical point (QCP) compared with CePt3Si. La2Pt8P shows normal metallic behavior and no superconductivity is observed above 0.28 K.