Ponomar, V. (2023). Crystal structures and magnetic properties of spinel ferrites synthesized from natural Fe–Mg–Ca carbonates. Materials Research Bulletin, 158, 112068. https://doi.org/10.1016/j.materresbull.2022.112068
Crystal structures and magnetic properties of spinel ferrites synthesized from natural Fe–Mg–Ca carbonates
1Fibre and Particle Engineering Research Unit, University of Oulu, Pentti Kaiteran katu 1, 90014 Oulu, Finland
|Online Access:||PDF Full Text (PDF, 2.3 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2023061454878
|Publish Date:|| 2023-06-14
Spinel ferrites with tunable magnetic properties were synthesized by the thermal treatment of Mg-substituted siderite and ankerite at different temperatures. The changes in magnetization and Curie temperature were monitored as a function of calcination temperature. A rapid increase in magnetization up to 25 Am²/kg was observed at 600 °С owing to spinel ferrite formation from a magnetite–magnesioferrite solid solution, followed by a moderate increase in magnetization (up to 30 Am²/kg) at 900 °С. Simultaneously, the Curie temperature decreased from 500 °C to 280 °C owing to Fe oxidation and cation redistribution. The resulting magnetic product (σS ≥ 30 Am²/kg, TC: 280 °C) exhibited a mixed spinel structure with a maghemite-like stoichiometry, (Fe³⁺, Mg)(Fe³⁺, Mg)₂O3+ẟ, a crystallite size of 22 nm at 700 °C and 34 nm at 900 °C, and an increased unit cell length (a = 8.41 Å).
Materials research bulletin
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
216 Materials engineering
© 2022 The Author. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).