Low-temperature Mossbauer studies of the phase composition and structural stability of iron (III) oxide/hydroxide nanocomposite
| Autor: | A. B. Hrubiak, V. V. Moklyak, B. K. Ostafiychuk, Y. V. Yavorskyi, V.D. Fedoriv, S.O. Yuryev |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Physics QC1-999 Analytical chemistry Oxide effective magnetic field Quadrupole splitting engineering.material Hematite Condensed Matter Physics zeeman splitting chemistry.chemical_compound chemistry mossbauer magnetically ordered and paramagnetic components visual_art Phase (matter) iron (iii) oxide/hydroxide nanocomposite Mössbauer spectroscopy engineering visual_art.visual_art_medium General Materials Science Crystallite Physical and Theoretical Chemistry Lepidocrocite Iron(III) oxide-hydroxide |
| Zdroj: | Фізика і хімія твердого тіла, Vol 22, Iss 2, Pp 307-312 (2021) |
| ISSN: | 2309-8589 1729-4428 |
| Popis: | In article present the results of low-temperature Mossbauer studies of iron (III) oxide/hydroxide nanocomposite synthesized by the method of deposition. Based on these studies, the composition of the synthesized composite was revealed. The nanodispersed composite with a specific surface 280 m2/g is a hematite in the weakly disordered crystalline state (CSR 10 nm), and a lepidocrocite in the X-ray amorphous state (particles size 3-4 nm). The relative integral intensity of the Zeeman sextet, which corresponds to the magnetically ordered phase of hematite, is practically unchanged and is about 17%. The tendency to divide the magnetically ordered component into two sextets, which differ in quadrupole splitting QS= –0.21 mm/s and QS= 0.21 mm/s, respectively, is observed starting from a temperature of 190 K. As a result of annealing of the synthesized material at a temperature of 200°C, a slight redistribution (≈ 5%) of the content of paramagnetic and magnetically ordered components was recorded, which indicates the structural stability of the nanoparticles of the lepidocrocite γ-FeOOH phase at this temperature. Increase of annealing temperatures to 500oC leads to the predicted course of the phase transition γ-FеООH ® α-Fе2О3. The mechanism of growth of hematite crystallites during sintering due to fixation side faces of larger α-Fe2O3 phase of nanoparticles of the γ-FeOOH phase with simultaneous transformation of their crystal structure to side faces of larger α-Fe2O3 phase particles is presented. |
| Databáze: | OpenAIRE |
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