Electrical resistivity and thermodynamic properties of the ferromagnet Nd₂Pt₂In

The Nd₂Pt₂In compound was investigated by means of electrical resistivity ρ(T), heat capacity C_p(T), magnetic susceptibility χ(T), magnetization M(μ₀H) and magnetocaloric effect (MCE) measurements. The material orders ferromagnetically at T_C = 16 K with a second - order phase transition. In the ordered state, ρ(T) can be represented in terms of ferromagnetic (FM) spin - wave dispersion with an energy gap Δ_R = 13(1) K in zero field. In concert, the C_p(T) data in this region can be well described by the same model getting Δ_C = 8(1) K in zero field. Above T_C, the ρ(T) variation is characteristic of electron - phonon interaction in the presence of s−d scattering and crystalline-electric field (CEF). The 4f - electron specific heat shows a Schottky - type anomaly around 60 K associated with CEF. On the other hand, C_p(T) data of the non-magnetic homologue La₂Pt₂In can be described by the Debye - Einstein model, giving a Debye and Einstein temperature values of 190.3(5) K and 69.8(7) K respectively. At high temperatures, the χ(T) data follows the Curie - Weiss relation with an effective magnetic moment μ_eff = 3.61(2) μ_B and a Weiss temperature θ_p = 17(1) K. The magnitude of MCE was estimated from the isothermal magnetization data to be 6.25 J/(kg.K), 5.01 J/(kg.K), 3.18 J/(kg.K) and 0.47 J/(kg.K) for a field change of 7 T, 5 T, 3 T and 1 T, respectively. The characteristic behaviour of the isothermal magnetic entropy change points to a second - order character of the FM phase transition.