Atomistic simulation and ab initio study of the defect structure of spinel-related Li_0.5-0.5xMg_xFe_2-0.5xO₄

Widatallah, H. M.; Moore, E. A.; Babo, A. A.; Al-Barwani, M. S. and Elzain, M. (2012). Atomistic simulation and ab initio study of the defect structure of spinel-related Li_0.5-0.5xMg_xFe_2-0.5xO₄. Materials Research Bulletin, 47(12) pp. 3995–4000.

DOI: https://doi.org/10.1016/j.materresbull.2012.08.048

Abstract

The position of magnesium ions in Mg²⁺ -doped lithium ferrite of the composition Li_{0.5 0.5x}Mg_xFe_{2.5- 0.5x}O₄, which has been a matter of uncertainty among some experimentalists, is investigated using interatomic potential and ab initio DFT calculations. Among possible 19 defect structure models, some of which have been reported experimentally, the lowest energy is found for Mg²⁺ ions evenly replacing Li⁺ and Fe³⁺ ion on octahedral sites. This gives a decrease in magnetisation for the Mg²⁺ -doped ferrite relative to the un-doped lithium ferrite. The results suggest that some experimental observations of increased magnetisation of spinel lithium ferrite on Mg²⁺-doping could be due to substitution of Mg²⁺ or Li⁺ on tetrahedral sites at the high temperatures used in preparation of the solid and/or as the presence of undetected defects in the initial precursors.

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About

• Item ORO ID
• 34270
• Item Type
• Journal Item
• ISSN
• 0025-5408
• Keywords
• inorganic compounds; ceramics; crystal structure
• Academic Unit or School
• Faculty of Science, Technology, Engineering and Mathematics (STEM) > Life, Health and Chemical Sciences
  Faculty of Science, Technology, Engineering and Mathematics (STEM)
• Copyright Holders
• © 2012 Elsevier Ltd.
• Depositing User
• Elaine Moore