Preparation, heat capacity, magnetic properties, and the magnetocaloric effect of EuO

EuO was synthesized through the thermal reduction of Eu₂O₃ by a stoichiometric quantity of metallic Eu. According to the heat capacity and magnetic measurements, EuO undergoes a second-order phase transformation at ∼69K from the ferromagnetic to the paramagnetic state on heating. The magnetocaloric effect of EuO, both as the isothermal magnetic entropy change (ΔS_mag) and the adiabatic temperature change (ΔT_ad), was obtained from the heat-capacity data. Also, the magnetization isotherms were used to calculate ΔS_mag. EuO exhibits the magnetocaloric effect with a peak in the vicinity of the magnetic phase-transition temperature (∼69K ), the amplitude of which is comparable to other known magnetocaloric materials. The ΔS_mag calculated from the heat-capacity data is in excellent agreement with that calculated from the magnetization data.