Impact of Antiphase Boundaries on Structural, Magnetic and Vibrational Properties of Fe<sub>3</sub>Al
We performed a quantum-mechanical study of the effect of antiphase boundaries (APBs) on structural, magnetic and vibrational properties of Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></sema...
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MDPI AG
2020-10-01
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| Online Access: | https://www.mdpi.com/1996-1944/13/21/4884 |
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| author | Martin Friák Miroslav Černý Monika Všianská Mojmír Šob |
| author_facet | Martin Friák Miroslav Černý Monika Všianská Mojmír Šob |
| author_sort | Martin Friák |
| collection | DOAJ |
| description | We performed a quantum-mechanical study of the effect of antiphase boundaries (APBs) on structural, magnetic and vibrational properties of Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al compound. The studied APBs have the {001} crystallographic orientation of their sharp interfaces and they are characterized by a 1/2〈111〉 shift of atomic planes. There are two types of APB interfaces formed by either two adjacent planes of Fe atoms or by two adjacent planes containing both Fe and Al atoms. The averaged APB interface energy is found to be 80 mJ/m<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula> and we estimate the APB interface energy of each of the two types of interfaces to be within the range of 40–120 mJ/m<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula>. The studied APBs affect local magnetic moments of Fe atoms near the defects, increasing magnetic moments of Fe<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mi>II</mi></msup></semantics></math></inline-formula> atoms by as much as 11.8% and reducing those of Fe<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mi mathvariant="normal">I</mi></msup></semantics></math></inline-formula> atoms by up to 4%. When comparing phonons in the Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al with and without APBs within the harmonic approximation, we find a very strong influence of APBs. In particular, we have found a significant reduction of gap in frequencies that separates phonon modes below 7.9 THz and above 9.2 THz in the defect-free Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al. All the APBs-induced changes result in a higher free energy, lower entropy and partly also a lower harmonic phonon energy in Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al with APBs when compared with those in the defect-free bulk Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al. |
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| spelling | doaj.art-cad57d1095c24c52be6a7a818c4fa2682023-11-20T19:15:17ZengMDPI AGMaterials1996-19442020-10-011321488410.3390/ma13214884Impact of Antiphase Boundaries on Structural, Magnetic and Vibrational Properties of Fe<sub>3</sub>AlMartin Friák0Miroslav Černý1Monika Všianská2Mojmír Šob3Institute of Physics of Materials, v.v.i., Czech Academy of Sciences, Žižkova 22, CZ-616 62 Brno, Czech RepublicCentral European Institute of Technology (CEITEC), Brno University of Technology, Technická 2, CZ-616 69 Brno, Czech RepublicCentral European Institute of Technology (CEITEC), Brno University of Technology, Technická 2, CZ-616 69 Brno, Czech RepublicDepartment of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech RepublicWe performed a quantum-mechanical study of the effect of antiphase boundaries (APBs) on structural, magnetic and vibrational properties of Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al compound. The studied APBs have the {001} crystallographic orientation of their sharp interfaces and they are characterized by a 1/2〈111〉 shift of atomic planes. There are two types of APB interfaces formed by either two adjacent planes of Fe atoms or by two adjacent planes containing both Fe and Al atoms. The averaged APB interface energy is found to be 80 mJ/m<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula> and we estimate the APB interface energy of each of the two types of interfaces to be within the range of 40–120 mJ/m<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula>. The studied APBs affect local magnetic moments of Fe atoms near the defects, increasing magnetic moments of Fe<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mi>II</mi></msup></semantics></math></inline-formula> atoms by as much as 11.8% and reducing those of Fe<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mi mathvariant="normal">I</mi></msup></semantics></math></inline-formula> atoms by up to 4%. When comparing phonons in the Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al with and without APBs within the harmonic approximation, we find a very strong influence of APBs. In particular, we have found a significant reduction of gap in frequencies that separates phonon modes below 7.9 THz and above 9.2 THz in the defect-free Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al. All the APBs-induced changes result in a higher free energy, lower entropy and partly also a lower harmonic phonon energy in Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al with APBs when compared with those in the defect-free bulk Fe<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al.https://www.mdpi.com/1996-1944/13/21/4884Fe-Alantiphase boundariesmagnetismab initiostabilityphonons |
| spellingShingle | Martin Friák Miroslav Černý Monika Všianská Mojmír Šob Impact of Antiphase Boundaries on Structural, Magnetic and Vibrational Properties of Fe<sub>3</sub>Al Materials Fe-Al antiphase boundaries magnetism ab initio stability phonons |
| title | Impact of Antiphase Boundaries on Structural, Magnetic and Vibrational Properties of Fe<sub>3</sub>Al |
| title_full | Impact of Antiphase Boundaries on Structural, Magnetic and Vibrational Properties of Fe<sub>3</sub>Al |
| title_fullStr | Impact of Antiphase Boundaries on Structural, Magnetic and Vibrational Properties of Fe<sub>3</sub>Al |
| title_full_unstemmed | Impact of Antiphase Boundaries on Structural, Magnetic and Vibrational Properties of Fe<sub>3</sub>Al |
| title_short | Impact of Antiphase Boundaries on Structural, Magnetic and Vibrational Properties of Fe<sub>3</sub>Al |
| title_sort | impact of antiphase boundaries on structural magnetic and vibrational properties of fe sub 3 sub al |
| topic | Fe-Al antiphase boundaries magnetism ab initio stability phonons |
| url | https://www.mdpi.com/1996-1944/13/21/4884 |
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