Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study

Restrictions on the availability of rare earth metals create a strong demand for new rare-earth-free hard magnetic materials. In this study, we considered a large set of materials that are closely related to orthorhombic Fe3C (cementite) with the aim of characterizing trends in their intrinsic magne...

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Main Authors: Justyn Snarski-Adamski, Mirosław Werwiński, Justyna Rychły-Gruszecka
Format: Article
Language:English
Published: AIP Publishing LLC 2025-02-01
Series:APL Materials
Online Access:http://dx.doi.org/10.1063/5.0243334
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author Justyn Snarski-Adamski
Mirosław Werwiński
Justyna Rychły-Gruszecka
author_facet Justyn Snarski-Adamski
Mirosław Werwiński
Justyna Rychły-Gruszecka
author_sort Justyn Snarski-Adamski
collection DOAJ
description Restrictions on the availability of rare earth metals create a strong demand for new rare-earth-free hard magnetic materials. In this study, we considered a large set of materials that are closely related to orthorhombic Fe3C (cementite) with the aim of characterizing trends in their intrinsic magnetic properties, highlighting the relation between magnetic properties and the chemical composition, and identifying alloys that are optimal for applications. A comprehensive analysis was conducted on the full concentration ranges of hexagonal (ϵ) and orthorhombic (θ) phases of (Fe–Co)3C, (Fe–Co)3(B–C), (Fe–Co)3(C–N), and their alloys with 3d, 4d, and 5d transition metals. The calculations were performed using the density functional theory implemented in the full-potential local-orbital code. Calculated properties included formation energies, Curie temperatures, magnetic moments, magnetocrystalline anisotropy energies (MAEs), and magnetic hardnesses. The considered compositions exhibit a range of magnetic properties, including soft, semi-hard, and hard magnetic. The materials most promising for hard-magnetic applications are selected Co-rich orthorhombic and hexagonal (Fe, Co)3C alloys. The calculation results do not indicate that substituting with transition metals increases the potential of the alloys for permanent magnet applications. A significant drawback of alloying orthorhombic θ–Fe3C (cementite) with transition metals is the notable decline in the Curie temperature. Among the positive outcomes, we found that a considerable proportion of the orthorhombic Co3(B–C–N) alloys are magnetically hard, of which boron substitution raises the Curie temperature and improves stability. By mapping the dependence of MAE on the concentration of elements covering both the 3d (from Fe to Co) and 2p (from B, through C, to N) positions, we have demonstrated for the first time the near isoelectronic nature of MAE. The latter observation may be particularly useful in designing compositions of new magnetically hard materials.
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spelling doaj-art-ba1e16be22ef4334923dc94108b855412025-08-20T03:15:57ZengAIP Publishing LLCAPL Materials2166-532X2025-02-01132021117021117-1810.1063/5.0243334Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles studyJustyn Snarski-Adamski0Mirosław Werwiński1Justyna Rychły-Gruszecka2Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, PolandInstitute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, PolandInstitute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, PolandRestrictions on the availability of rare earth metals create a strong demand for new rare-earth-free hard magnetic materials. In this study, we considered a large set of materials that are closely related to orthorhombic Fe3C (cementite) with the aim of characterizing trends in their intrinsic magnetic properties, highlighting the relation between magnetic properties and the chemical composition, and identifying alloys that are optimal for applications. A comprehensive analysis was conducted on the full concentration ranges of hexagonal (ϵ) and orthorhombic (θ) phases of (Fe–Co)3C, (Fe–Co)3(B–C), (Fe–Co)3(C–N), and their alloys with 3d, 4d, and 5d transition metals. The calculations were performed using the density functional theory implemented in the full-potential local-orbital code. Calculated properties included formation energies, Curie temperatures, magnetic moments, magnetocrystalline anisotropy energies (MAEs), and magnetic hardnesses. The considered compositions exhibit a range of magnetic properties, including soft, semi-hard, and hard magnetic. The materials most promising for hard-magnetic applications are selected Co-rich orthorhombic and hexagonal (Fe, Co)3C alloys. The calculation results do not indicate that substituting with transition metals increases the potential of the alloys for permanent magnet applications. A significant drawback of alloying orthorhombic θ–Fe3C (cementite) with transition metals is the notable decline in the Curie temperature. Among the positive outcomes, we found that a considerable proportion of the orthorhombic Co3(B–C–N) alloys are magnetically hard, of which boron substitution raises the Curie temperature and improves stability. By mapping the dependence of MAE on the concentration of elements covering both the 3d (from Fe to Co) and 2p (from B, through C, to N) positions, we have demonstrated for the first time the near isoelectronic nature of MAE. The latter observation may be particularly useful in designing compositions of new magnetically hard materials.http://dx.doi.org/10.1063/5.0243334
spellingShingle Justyn Snarski-Adamski
Mirosław Werwiński
Justyna Rychły-Gruszecka
Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study
APL Materials
title Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study
title_full Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study
title_fullStr Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study
title_full_unstemmed Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study
title_short Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study
title_sort magnetic hardness of hexagonal and orthorhombic fe3c co3c fe co 3c and their alloys with boron nitrogen and transition metals a first principles study
url http://dx.doi.org/10.1063/5.0243334
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