Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects

We have employed first-principles calculations based on density functional theory (DFT) to investigate the underlying physics of unusual magnetism in Mn-doped MgO surface. We have studied two distinct scenarios. In the first one, two Mn atoms are substitutionally added to the surface, occupying the...

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Main Authors:	Panigrahi, Puspamitra, Araujo, C Moyses, Hussen, Tanveer, Ahuja, Rajeev
Format:	Online
Language:	English
Published:	Taylor & Francis 2014
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5090529/

id	pubmed-5090529
recordtype	oai_dc
spelling	pubmed-50905292016-11-22 Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects Panigrahi, Puspamitra Araujo, C Moyses Hussen, Tanveer Ahuja, Rajeev Papers We have employed first-principles calculations based on density functional theory (DFT) to investigate the underlying physics of unusual magnetism in Mn-doped MgO surface. We have studied two distinct scenarios. In the first one, two Mn atoms are substitutionally added to the surface, occupying the Mg sites. Both are stabilized in the Mn valence state carrying a local moment of 4.3 having a high-spin configuration. The magnetic interaction between the local moments display a very short-ranged characteristic, decaying very quickly with distance, and having antiferromagnetic ordering lower in energy. The energetics analysis also indicates that the Mn ions prefer to stay close to each other with an oxygen atom bridging the local interaction. In the second scenario, we started exploring the effect of native defects on the magnetism by crafting both Mg and O vacancies, which are p- and n-type defects, respectively. It is found that the electrons and holes affect the magnetic interaction between Mn ions in a totally different manner. The n-type defect leads to very similar magnetism, with the AFM configuration being energetically preferred. However, in the presence of Mg vacancy, the situation is quite different. The Mn atoms are further oxidized, giving rise to mixed Mn(d) ionic states. As a consequence, the Mn atoms couple ferromagnetically, when placed in the close configuration, and the obtained electronic structure is coherent with the double-exchange type of magnetic interaction. To guarantee the robustness of our results, we have benchmarked our calculations with three distinct theory levels, namely DFT-GGA, DFT-GGA+U and DFT-hybrid functionals. On the surface, the Mg vacancy displays lower formation energy occurring at higher concentrations. Therefore, our model systems can be the basis to explain a number of controversial results regarding transition metal doped oxides. Taylor & Francis 2014-06-13 /pmc/articles/PMC5090529/ /pubmed/27877684 http://dx.doi.org/10.1088/1468-6996/15/3/035008 Text en © 2014 National Institute for Materials Science http://creativecommons.org/licenses/by-nc-sa/3.0/ Content from this work may be used under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 licence (http://creativecommons.org/licenses/by-nc-sa/3.0/) . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Panigrahi, Puspamitra Araujo, C Moyses Hussen, Tanveer Ahuja, Rajeev
spellingShingle	Panigrahi, Puspamitra Araujo, C Moyses Hussen, Tanveer Ahuja, Rajeev Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects
author_facet	Panigrahi, Puspamitra Araujo, C Moyses Hussen, Tanveer Ahuja, Rajeev
author_sort	Panigrahi, Puspamitra
title	Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects
title_short	Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects
title_full	Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects
title_fullStr	Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects
title_full_unstemmed	Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects
title_sort	crafting ferromagnetism in mn-doped mgo surfaces with p-type defects
description	We have employed first-principles calculations based on density functional theory (DFT) to investigate the underlying physics of unusual magnetism in Mn-doped MgO surface. We have studied two distinct scenarios. In the first one, two Mn atoms are substitutionally added to the surface, occupying the Mg sites. Both are stabilized in the Mn valence state carrying a local moment of 4.3 having a high-spin configuration. The magnetic interaction between the local moments display a very short-ranged characteristic, decaying very quickly with distance, and having antiferromagnetic ordering lower in energy. The energetics analysis also indicates that the Mn ions prefer to stay close to each other with an oxygen atom bridging the local interaction. In the second scenario, we started exploring the effect of native defects on the magnetism by crafting both Mg and O vacancies, which are p- and n-type defects, respectively. It is found that the electrons and holes affect the magnetic interaction between Mn ions in a totally different manner. The n-type defect leads to very similar magnetism, with the AFM configuration being energetically preferred. However, in the presence of Mg vacancy, the situation is quite different. The Mn atoms are further oxidized, giving rise to mixed Mn(d) ionic states. As a consequence, the Mn atoms couple ferromagnetically, when placed in the close configuration, and the obtained electronic structure is coherent with the double-exchange type of magnetic interaction. To guarantee the robustness of our results, we have benchmarked our calculations with three distinct theory levels, namely DFT-GGA, DFT-GGA+U and DFT-hybrid functionals. On the surface, the Mg vacancy displays lower formation energy occurring at higher concentrations. Therefore, our model systems can be the basis to explain a number of controversial results regarding transition metal doped oxides.
publisher	Taylor & Francis
publishDate	2014
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5090529/
_version_	1613707868910911488

Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects

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