Synthesis and X-ray diffraction and calorimetric studies of LaLiMnFeO5 and LaCsMnFeO5 ferrites

Ferrites LaLiMnFeO₅ and LaCsMnFeO₅ were synthesized for the first time by ceramic technology from mixtures of lanthanum(III), manganese, and iron(III) oxides with lithium or cesium carbonate. The compounds were shown by X-ray diffraction to crystallize in the orthorhombic system; the unit cell parameters were determined. The heat capacities were found experimentally for 298.15–673 K. Equations for the heat capacities as a function of temperature were derived and used to calculate the thermodynamic functions C _p ⁰ (T), S ⁰(T), H ⁰(T)?H ⁰(298.15), and Φ**(T) for the above temperature range.