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Formation of Oxide Phases in the System Eu₂O₃ - Fe₂O₃

Mira Ristić ; Ruđer Bošković Institute, P. O. Box 180, HR-10002 Zagreb, Croatia
Israel Nowik ; Racah Institute of Physics, The Hebrevu University, Jerusalem, 91904 Israel
Stanko Popović ; Department of Physics, Faculty of Science, University of Zagreb, P. O. Box 331, HR-10002 Zagreb, Croatia
Svetozar Musić ; Ruđer Bošković Institute, P. O. Box 180, HR-10002 Zagreb, Croatia

Sažetak

Evolution of oxide phases in the Eu₂O₃-Fe₂O₃ system was investigated by X-ray powder diffraction, 57Fe and 151Eu Mössbauer spectroscopy and Fourier transform infrared spectroscopy. Samples were prepared by the solid state reaction of the corresponding oxides for two molar ratios, Eu₂O₃ : Fe₂O₃ = 1:1 and 3:5. After heating the mixed oxide powder with molar ratio Eu₂O₃ : Fe₂O₃ = 1 : 1 up to 900 °C, EuFeO₃ and traces of Eu₂O₃ were detected by XRD, while after additional heating up to 1100 °C traces of Eu₃Fe₅O₁₂ (EuIG) were also detected. 57Fe and 151Eu Mössbauer spectroscopy showed the presence of EuFeO₃. For the molar ratio Eu₂O₃ : Fe₂O₃ = 3 : 5, EuIG was formed between 1100 and 1300 °C. In the sample produced at 1300 °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 EuFeO₃ and EuIG are discussed. Mechanical activation of the mixed oxide powder was important for the formation of polycrystalline EuIG, as a single phase.

Ključne riječi

X-ray powder diffraction; ⁵⁷Fe and ¹⁵¹Eu Mössbauer; FT-IR spectroscopy; europium iron garnet; europium orthoferrite

Hrčak ID:

132069

URI

https://hrcak.srce.hr/132069

Datum izdavanja:

5.6.2000.

Posjeta: 919 *