Formation of oxide phases in the system Eu2O3-Fe2O3

Evolution of oxide phases in the Eu(2)O(3)-Fe(2)O(3) system was investigated by X-ray powder diffraction, (57)Fe and (151)Eu Mossbauer spectroscopy and Fourier transform infrared spectroscopy. Samples were prepared by the solid state reaction of the corresponding oxides for two molar ratios, Eu(2)O(3) : Fe(2)O(3) = 1 : 1 and 3 : 5. After heating the mixed oxide powder with molar ratio Eu(2)O(3) : Fe(2)O(3) =1:1 up to 900 degrees C, EuFeO(3) and traces of Eu(2)O(3) were detected by XRD, while after additional heating up to 1100 degrees C traces of Eu(3)Fe(5)O(12) (EuIG) were also detected. (57)Fe and (151)Eu Mossbauer spectroscopy showed the presence of EuFeO(3). For the molar ratio Eu(2)O(3) : Fe(2)O(3) = 3 : 5, EuIG was formed between 1100 and 1300 degrees C. In the sample produced at 1300 degrees C, the measured hyperfine fields at the iron sites, at room temperature, were H(a)= 495 and H(d) = 402 kOe, and the hyperfine fields at the europium sites, at 90 K, were H(I) = 631 kOe and H(II) = 572 kOe. Europium orthoferrite was the intermediate phase in the garnet formation. Assignations of IR bands corresponding to EuFeO(3) and EuIG are discussed. Mechanical activation of the mixed oxide powder was important for the formation of polycrystalline EuIG, as a single phase.