Magnetic and magnetocaloric properties of as-cast gd2 in

This paper presents results of experimental studies of magnetic and magnetocaloric properties of as-cast polycrystalline samples of a Gd 2 In intermetallic compound, which crystallizes into a hexagonal structure of the Ni 2 In type. Measurements of the field and temperature dependences of the magnetization carried out in a temperature range from 50 to 300 K and in magnetic fields up to 3 T showed that the as-cast Gd 2 In samples undergo ferromagnetic ordering upon cooling below Curie temperature Т С =194 K. With further cooling, a metamagnetic transition from the ferromagnetic into an antiferromagnetic phase is observed at a temperature T m = 95 K, which is accompanied by pronounced anomalies in the temperature and field dependences of the magnetization. An external magnetic field stabilizes the ferromagnetic phase, shifting T m toward low temperatures. The isothermal magnetic entropy change in the Δ S m , calculated using the Maxwell relation, shows a peak at the Curie temperature, which, when the magnetic field changes from 0 to 3 T, reaches its maximum value Δ S m = −3.25 J / kg ∙ K. The temperature dependence of Δ S m clearly indicates a crossover of the magnetocaloric effect from direct to inverse one, which occurs in the vicinity of the metamagnetic transition. The experimental data obtained in our work on unannealed Gd 2 In samples are in a good qualitative and quantitative agreement with the data published for the annealed Gd 2 In samples. Thus, the results of this work indicate that the attainment of a homogeneous state in polycrystalline Gd 2 In samples, which can affect their magnetic properties, can occur during cooling of the as-cast ingot on a cold crucible and does not require an additional heat treatment.