@article{Ostafiychuk_Moklyak_Fedoriv_Hrubiak_Yavorskyi_Yuryev_2021, title={Low-temperature Mossbauer studies of the phase composition and structural stability of iron (III) oxide/hydroxide nanocomposite: Array}, volume={22}, url={https://journals.pnu.edu.ua/index.php/pcss/article/view/4933}, DOI={10.15330/pcss.22.2.307-312}, abstractNote={<p>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 m<sup>2</sup>/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 Q<sub>S</sub>= –0.21 mm/s and Q<sub>S</sub>= 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 500<sup>o</sup>C leads to the predicted course of the phase transition γ-FеООH ® α-Fе<sub>2</sub>О<sub>3</sub>. The mechanism of growth of hematite crystallites during sintering due to fixation side faces of larger α-Fe<sub>2</sub>O<sub>3</sub> phase of nanoparticles of the γ-FeOOH phase with simultaneous transformation of their crystal structure to side faces of larger α-Fe<sub>2</sub>O<sub>3</sub> phase particles is presented.</p>}, number={2}, journal={Physics and Chemistry of Solid State}, author={Ostafiychuk, B.K. and Moklyak, V.V. and Fedoriv, V.D. and Hrubiak, A.B. and Yavorskyi, Yu.V. and Yuryev, S.O.}, year={2021}, month={May}, pages={307–312} }