Calorimetric study of AlNd2: Heat capacity. Standard Gibbs energy of formation

The thermodynamic properties of the magnetic phase transition from ferro- to para-phases of AlNd2 were directly investigated by using calorimetry. The standard entropies of formation, ΔfSm,T∘, of the ferro- and paramagnetic phases were determined by measuring the heat capacity, Cp,m∘, from 2 to 300 K. The standard enthalpies of formation, ΔfHm,T∘, of them were determined by combining Cp,m∘ with the standard enthalpy of formation, ΔfHm,298∘, at 298 K obtained by acid solution calorimetry. The standard Gibbs energies of formation, ΔfGm,T∘, of the ferro- and paramagnetic phases of AlNd2 were determined from their ΔfSm,T∘ and ΔfHm,T∘ values. The ΔfGm,T∘ values indicate that the magnetic phase transition from ferro- to paramagnetic phases occurs at 39.59 K, consistent with the observed phase transition at 39.59 K.

► The standard entropies of formation of the ferro and paramagnetic phases of AlNd2 were determined by measuring the heat capacity from 2 to 300 K. ► The standard Gibbs energies of formation of them were determined by combining Cp with the standard enthalpy of formation at 298 K obtained by acid solution calorimetry. ► The standard Gibbs energies of formation indicate that the magnetic phase transition from ferro to paramagnetic phases occurs at 39.59 K, consistent with the observed phase transition at 39.59 K.