Physics:Half-metal
A half-metal is any substance that acts as a conductor to electrons of one spin orientation, but as an insulator or semiconductor to those of the opposite orientation. Although all half-metals are ferromagnetic (or ferrimagnetic), most ferromagnets are not half-metals. Many of the known examples of half-metals are oxides, sulfides, or Heusler alloys.[1] Types of half-metallic compounds theoretically predicted so far include some Heusler alloys, such as Co
2FeSi, NiMnSb, and PtMnSb; some Si-containing half–Heusler alloys with Curie temperatures over 600 K, such as NiCrSi and PdCrSi; some transition-metal oxides, including rutile structured CrO
2; some perovskites, such as LaMnO
3 and SeMnO
3; and a few more simply structured zincblende (ZB) compounds, including CrAs and superlattices. NiMnSb and CrO
2 have been experimentally determined to be half-metals at very low temperatures.
In half-metals, the valence band for one spin orientation is partially filled while there is a gap in the density of states for the other spin orientation. This results in conducting behavior for only electrons in the first spin orientation. In some half-metals, the majority spin channel is the conducting one while in others the minority channel is.[2]
Half-metals were first described in 1983, as an explanation for the electrical properties of manganese-based Heusler alloys.[3]
Some notable half-metals are chromium(IV) oxide, magnetite, and lanthanum strontium manganite (LSMO),[1] as well as chromium arsenide. Half-metals have attracted some interest for their potential use in spintronics.
References
- ↑ 1.0 1.1 Coey, J.M.D.; Venkatesan, M. (2002). "Half-metallic ferromagnetism: Example of CrO2". Journal of Applied Physics 91 (10): 8345–50. doi:10.1063/1.1447879. Bibcode: 2002JAP....91.8345C.
- ↑ Rostami, Mohammad; Afkani, Mohammad; Torkamani, Mohammad Reza; Kanjouri, Faramarz (2020-07-01). "Bulk and surface DFT investigations of the electronic and magnetic properties of CsXNO (X = Mg, Ca and Sr) quaternary Heusler alloys". Materials Chemistry and Physics 248: 122923. doi:10.1016/j.matchemphys.2020.122923. ISSN 0254-0584. https://www.sciencedirect.com/science/article/pii/S0254058420302996.
- ↑ de Groot, R. A.; Mueller, F. M.; Engen, P. G. van; Buschow, K. H. J. (20 June 1983). "New Class of Materials: Half-Metallic Ferromagnets". Physical Review Letters 50 (25): 2024–2027. doi:10.1103/PhysRevLett.50.2024. Bibcode: 1983PhRvL..50.2024D. https://pure.rug.nl/ws/files/3419075/1983PhysRevLettdeGroot.pdf.
Further reading
- Guezlane, M; Baaziz, H; El Haj Hassan, F; Charifi, Z; Djaballah, Y (2016). "Electronic, magnetic and thermal properties of Co2CrxFe1−xX (X=Al, Si) Heusler alloys: First-principles calculations". Journal of Magnetism and Magnetic Materials 414: 219–26. doi:10.1016/j.jmmm.2016.04.056. Bibcode: 2016JMMM..414..219G.
- Son, Young-Woo; Cohen, Marvin L; Louie, Steven G (2006). "Half-metallic graphene nanoribbons". Nature 444 (7117): 347–9. doi:10.1038/nature05180. PMID 17108960. Bibcode: 2006Natur.444..347S.
- http://www-users.york.ac.uk/~ah566/research/half_metals.html[full citation needed][yes|permanent dead link|dead link}}]
- http://www.tcd.ie/Physics/People/Michael.Coey/oxsen/newsletter/january98/halfmeta.htm[full citation needed]
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