Electrical resistivity and thermodynamic properties of the ferromagnet Nd2Pt2In

The Nd2Pt2In compound was investigated by means of electrical resistivity ρ(T), heat capacity Cp(T), magnetic susceptibility χ(T), magnetization M(μ0H) and magnetocaloric effect (MCE) measurements. The material orders ferromagnetically at TC  = 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 ΔR  = 13(1) K in zero field. In concert, the Cp(T) data in this region can be well described by the same model getting ΔC  = 8(1) K in zero field. Above TC, 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, Cp(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 μeff  = 3.61(2) μB and a Weiss temperature θp  = 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.