First-principles study of the inversion thermodynamics and electronic structure of FeM2X4 (thio)spinels (M = Cr, Mn, Co, Ni; X = O, S)

Santos-Carballal, David ORCID: https://orcid.org/0000-0002-3199-9588, Roldan, Alberto, Grau-Crespo, Ricardo and de Leeuw, Nora H. ORCID: https://orcid.org/0000-0002-8271-0545 2015. First-principles study of the inversion thermodynamics and electronic structure of FeM2X4 (thio)spinels (M = Cr, Mn, Co, Ni; X = O, S). Physical Review B 91 (19) , 195106. 10.1103/PhysRevB.91.195106

Preview

PDF - Published Version Available under License Creative Commons Attribution. Download (926kB) | Preview

Abstract

FeM2X4 spinels, with the magnetite structure, where M is a transition metal and X is oxygen or sulfur, are candidate materials for spin filters, one of the key devices in spintronics. We present here a computational study of the inversion thermodynamics and the electronic structure of these (thio)spinels for M=Cr,Mn,Co,Ni, using calculations based on the density functional theory with on-site Hubbard corrections (DFT+U). The analysis of the configurational free energies shows that different behavior is expected for the equilibrium cation distributions in these structures: FeCr2X4 and FeMn2S4 are fully normal, FeNi2X4 and FeCo2S4 are intermediate, and FeCo2O4 and FeMn2O4 are fully inverted. We have analyzed the role played by the size of the ions and by the crystal field stabilization effects in determining the equilibrium inversion degree. We also discuss how the electronic and magnetic structure of these spinels is modified by the degree of inversion, assuming that this could be varied from the equilibrium value. We have obtained electronic densities of states for the completely normal and completely inverse cation distribution of each compound. FeCr2X4,FeMn2X4,FeCo2O4, and FeNi2O4 are half-metals in the ferrimagnetic state when Fe is in tetrahedral positions. When M is filling the tetrahedral positions, the Cr-containing compounds and FeMn2O4 are half-metallic systems, while the Co and Ni spinels are insulators. The Co and Ni sulfide counterparts are metallic for any inversion degree together with the inverse FeMn2S4. Our calculations suggest that the spin filtering properties of the FeM2X4 (thio)spinels could be modified via the control of the cation distribution through variations in the synthesis conditions.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Advanced Research Computing @ Cardiff (ARCCA) Chemistry
Subjects:	Q Science > QD Chemistry
Publisher:	American Physical Society
ISSN:	1098-0121
Date of First Compliant Deposit:	30 March 2016
Last Modified:	16 Jun 2023 23:30
URI:	https://orca.cardiff.ac.uk/id/eprint/73195

Citation Data

Cited 84 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item