Hematite: Morin temperature of nanoparticles with different size

0538738 - FZÚ 2021 RIV NL eng J - Journal Article
Kubániová, D. - Kubíčková, L. - Kmječ, T. - Závěta, Karel - Nižňanský, D. - Brázda, Petr - Klementová, Mariana - Kohout, J.
Hematite: Morin temperature of nanoparticles with different size.
Journal of Magnetism and Magnetic Materials. Roč. 475, April (2019), s. 611-619. ISSN 0304-8853. E-ISSN 1873-4766
R&D Projects: GA ČR GA16-04340S
Institutional support: RVO:68378271
Keywords : alpha-Fe₂O₃ * Morin transition * Spin-reorientation transition * Mossbauer spectroscopy * Finite-scaling model
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 2.717, year: 2019
Method of publishing: Limited access
https://doi.org/10.1016/j.jmmm.2018.11.126

A spin-reorientation transition from a weakly ferromagnetic (WF) to an antiferromagnetic (AF) spin ordering in hematite (α-Fe2O3) during cooling occurs at Morin temperature (TM∼264 K for bulk). The transition is strongly size dependent and TM generally decreases with the decreasing volume of the particles. We report an investigation on nanoparticles prepared by hydrothermal method and sol–gel technique (in silica) of pure α-Fe2O3 phase as confirmed by XRD differing in the median size. By means of Mössbauer spectra acquired between 4.2 and 300 K, we determined the relative concentrations of magnetic phases (WF and AF) within the 57Fe enriched sample and searched for the best finite-scaling theoretical model (mean-field, 3D Heisenberg, Ising) describing the derived size dependence of Morin temperature of the nanoparticles with a log-normal size distribution.
Permanent Link: http://hdl.handle.net/11104/0316475