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 similar to 69 K from the ferromagnetic to the paramagnetic state on heating. The magnetocaloric effect of EuO, both as the isothermal magnetic entropy change (Delta S-mag) and the adiabatic temperature change (Delta T-ad), was obtained from the heat-capacity data. Also, the magnetization isotherms were used to calculate Delta S-mag. EuO exhibits the magnetocaloric effect with a peak in the vicinity of the magnetic phase-transition temperature (similar to 69 K), the amplitude of which is comparable to other known magnetocaloric materials. The Delta S-mag calculated from the heat-capacity data is in excellent agreement with that calculated from the magnetization data. (C) 2005 American Institute of Physics.