Distortion induced magnetic phase transition in cubic BaFeO 3

Rahman, Gul; Morbec, Juliana M.; Ferradás, Rubén; García-Suárez, Víctor M.; English, Niall J.

Abstract

The electronic and magnetic structures of cubic BaFeO3 (BFO) in the ferromagnetic (FM) and antiferromagnetic (AFM) states are studied using density functional theory (DFT) with the local spin density approximation (LSDA) and the generalized gradient approximation (GGA), with and without a Coulomb U term. Our LSDA/GGA and LSDA+U/GGA+U results show that cubic BFO has a FM ground state, in agreement with recent experimental studies. Two types of distortions, denoted as D1 and D2, are considered. The source of the distortion in the D1 (D2) case is the displacement of the oxygen (iron) atoms from their equilibrium positions. FM to ferrimagnetic (FIM) and FM to AFM magnetic phase transitions are found in the D1 and D2 distortions, respectively. Larger strains are required for the FM–AFM transition as compared to the FM–FIM. DFT+U calculations also show that the magnetic moments dramatically decrease at large strains due to strong overlapping between the iron and oxygen atoms. The origin of these transitions is discussed in terms of a competition between double exchange and superexchange interactions. From these results it is possible to conclude that oxygen and iron displacements are responsible for the magnetic phase transitions and the reduction of the magnetic moments in BFO.

Citation

Rahman, G., Morbec, J. M., Ferradás, R., García-Suárez, V. M., & English, N. J. (2016). Distortion induced magnetic phase transition in cubic BaFeO 3. Journal of Magnetism and Magnetic Materials, 401, 1097-1105. https://doi.org/10.1016/j.jmmm.2015.11.002

• Journal Article Type: Article
• Publication Date: 2016-03
• Deposit Date: May 30, 2023
• Journal: Journal of Magnetism and Magnetic Materials
• Print ISSN: 0304-8853
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 401
• Pages: 1097-1105
• DOI: https://doi.org/10.1016/j.jmmm.2015.11.002
• Keywords: Condensed Matter Physics; Electronic, Optical and Magnetic Materials
• Additional Information: This article is maintained by: Elsevier; Article Title: Distortion induced magnetic phase transition in cubic BaFeO3; Journal Title: Journal of Magnetism and Magnetic Materials; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.jmmm.2015.11.002; Content Type: article; Copyright: Copyright © 2015 Elsevier B.V. All rights reserved.