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{{distinguish|semi-metal}}
{{distinguish|semi-metal}}
[[Image:Half metar sattar.JPG|thumb|The electronic structure of a half-metal. <math>E_f</math> is the [[fermi energy]], <math>N(E)</math> is the [[density of states]] for spin down (on the left) and spin up (on the right). In this case, the half-metal is conducting in the minority spin channel.]]
[[Image:Half metar sattar.JPG|thumb|The electronic structure of a half-metal. <math>E_f</math> is the [[Fermi level]], <math>N(E)</math> is the [[density of states]] for spin down (on the left) and spin up (on the right). In this case, the half-metal is conducting in the minority spin channel.]]


A '''half-metal''' is any substance that acts as a [[Electrical conductor|conductor]] to [[electron]]s of one [[spin (physics)|spin]] orientation, but as an [[Electrical insulation|insulator]] or [[semiconductor]] to those of the opposite orientation. Although all half-metals are [[Ferromagnetism|ferromagnetic]] (or [[Ferrimagnetism|ferrimagnetic]]), most ferromagnets are not half-metals. Many of the known examples of half-metals are [[oxide]]s, [[sulfide]]s, or [[Heusler alloy]]s.<ref name=COEY02>{{cite journal |first1=J.M.D. |last1=Coey |first2=M.|last2=Venkatesan|year=2002 |title=Half-metallic ferromagnetism: Example of CrO2 |journal=Journal of Applied Physics |volume=91 |issue=10 |pages=8345–50 |doi=10.1063/1.1447879 |bibcode = 2002JAP....91.8345C }}</ref>
A '''half-metal''' is any substance that acts as a [[Electrical conductor|conductor]] to [[electron]]s of one [[Spin (physics)|spin]] orientation, but as an [[Electrical insulation|insulator]] or [[semiconductor]] to those of the opposite orientation. Although all half-metals are [[Ferromagnetism|ferromagnetic]] (or [[Ferrimagnetism|ferrimagnetic]]), most ferromagnets are not half-metals. Many of the known examples of half-metals are [[oxide]]s, [[sulfide]]s, or [[Heusler alloy]]s.<ref name=COEY02>{{cite journal |first1=J.M.D. |last1=Coey |first2=M.|last2=Venkatesan|year=2002 |title=Half-metallic ferromagnetism: Example of CrO2 |journal=Journal of Applied Physics |volume=91 |issue=10 |pages=8345–50 |doi=10.1063/1.1447879 |bibcode = 2002JAP....91.8345C}}</ref> Types of half-metallic compounds theoretically predicted so far include some Heusler alloys, such as {{chem2|Co2FeSi}}, 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 {{chem2|CrO2}}; some perovskites, such as {{chem2|LaMnO3}} and {{chem2|SeMnO3}}; and a few more simply structured zincblende (ZB) compounds, including CrAs and superlattices. NiMnSb and {{chem2|CrO2}} 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.{{fact|date=January 2018}}
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.<ref>{{Cite journal |last=Rostami |first=Mohammad |last2=Afkani |first2=Mohammad |last3=Torkamani |first3=Mohammad Reza |last4=Kanjouri |first4=Faramarz |date=2020-07-01 |title=Bulk and surface DFT investigations of the electronic and magnetic properties of CsXNO (X = Mg, Ca and Sr) quaternary Heusler alloys |url=https://www.sciencedirect.com/science/article/pii/S0254058420302996 |journal=Materials Chemistry and Physics |volume=248 |pages=122923 |doi=10.1016/j.matchemphys.2020.122923 |issn=0254-0584}}</ref>


Half-metals were first described in 1983, as an explanation for the electrical properties of Mn-based [[Heusler alloy]]s.<ref>{{cite journal|title=New Class of Materials: Half-Metallic Ferromagnets|publisher=Phys. Rev. Lett.|author=R. A. de Groot, F. M. Mueller, P. G. van Engen, and K. H. J. Buschow|year=1983|volume=50|issue=25|page=2024|doi=10.1103/PhysRevLett.50.2024}}</ref>
Half-metals were first described in 1983, as an explanation for the electrical properties of [[manganese]]-based [[Heusler alloy]]s.<ref>{{cite journal |last1=de Groot |first1=R. A. |last2=Mueller |first2=F. M. |last3=Engen |first3=P. G. van |last4=Buschow |first4=K. H. J. |title=New Class of Materials: Half-Metallic Ferromagnets |journal=Physical Review Letters |date=20 June 1983 |volume=50 |issue=25 |pages=2024–2027 |doi=10.1103/PhysRevLett.50.2024 |bibcode=1983PhRvL..50.2024D |url=https://pure.rug.nl/ws/files/3419075/1983PhysRevLettdeGroot.pdf |hdl=11370/e3946f6b-8acb-4e0a-80cf-735506203f25 |hdl-access=free}}</ref>


Some notable half-metals are [[chromium(IV) oxide]], [[magnetite]], and [[lanthanum strontium manganite]] (LSMO),<ref name=COEY02/> as well as [[chromium arsenide]]. Half-metals have attracted some interest for their potential use in [[spintronics]].{{fact|date=January 2018}}
Some notable half-metals are [[chromium(IV) oxide]], [[magnetite]], and [[lanthanum strontium manganite]] (LSMO),<ref name=COEY02/> as well as [[chromium arsenide]]. Half-metals have attracted some interest for their potential use in [[spintronics]].


==References==
==References==
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==Further reading==
==Further reading==
*{{cite journal |doi=10.1016/j.jmmm.2016.04.056 |title=Electronic, magnetic and thermal properties of Co2CrxFe1−xX (X=Al, Si) Heusler alloys: First-principles calculations |journal=Journal of Magnetism and Magnetic Materials |volume=414 |pages=219–26 |year=2016 |last1=Guezlane |first1=M |last2=Baaziz |first2=H |last3=El Haj Hassan |first3=F |last4=Charifi |first4=Z |last5=Djaballah |first5=Y |bibcode=2016JMMM..414..219G }}
*{{cite journal |doi=10.1016/j.jmmm.2016.04.056 |title=Electronic, magnetic and thermal properties of Co2CrxFe1−xX (X=Al, Si) Heusler alloys: First-principles calculations |journal=Journal of Magnetism and Magnetic Materials |volume=414 |pages=219–26 |year=2016 |last1=Guezlane |first1=M |last2=Baaziz |first2=H |last3=El Haj Hassan |first3=F |last4=Charifi |first4=Z |last5=Djaballah |first5=Y |bibcode=2016JMMM..414..219G}}
*{{cite journal |doi=10.1038/nature05180 |pmid=17108960 |title=Half-metallic graphene nanoribbons |journal=Nature |volume=444 |issue=7117 |pages=347–9 |year=2006 |last1=Son |first1=Young-Woo |last2=Cohen |first2=Marvin L |last3=Louie |first3=Steven G |bibcode=2006Natur.444..347S |arxiv=cond-mat/0611600 }}
*{{cite journal |doi=10.1038/nature05180 |pmid=17108960 |title=Half-metallic graphene nanoribbons |journal=Nature |volume=444 |issue=7117 |pages=347–9 |year=2006 |last1=Son |first1=Young-Woo |last2=Cohen |first2=Marvin L |last3=Louie |first3=Steven G |bibcode=2006Natur.444..347S |arxiv=cond-mat/0611600 |s2cid=52851642}}
* http://www-users.york.ac.uk/~ah566/research/half_metals.html{{full|date=January 2018}}
* http://www-users.york.ac.uk/~ah566/research/half_metals.html{{full citation needed|date=January 2018}}{{Dead link|date=January 2020 |bot=InternetArchiveBot |fix-attempted=yes}}
* http://www.tcd.ie/Physics/People/Michael.Coey/oxsen/newsletter/january98/halfmeta.htm{{full|date=January 2018}}
* http://www.tcd.ie/Physics/People/Michael.Coey/oxsen/newsletter/january98/halfmeta.htm{{full citation needed|date=January 2018}}


{{DEFAULTSORT:Half-Metal}}
{{DEFAULTSORT:Half-Metal}}
[[Category:Metals]]
[[Category:Metals]]
[[Category:Spintronics]]
[[Category:Spintronics]]



{{CMP-stub}}
{{CMP-stub}}

Latest revision as of 14:30, 24 January 2024

Not to be confused with semi-metal.
The electronic structure of a half-metal. is the Fermi level, is the density of states for spin down (on the left) and spin up (on the right). In this case, the half-metal is conducting in the minority spin channel.

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 Co2FeSi, 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 CrO2; some perovskites, such as LaMnO3 and SeMnO3; and a few more simply structured zincblende (ZB) compounds, including CrAs and superlattices. NiMnSb and CrO2 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

[edit]
  1. ^ a b Coey, J.M.D.; Venkatesan, M. (2002). "Half-metallic ferromagnetism: Example of CrO2". Journal of Applied Physics. 91 (10): 8345–50. Bibcode:2002JAP....91.8345C. doi:10.1063/1.1447879.
  2. ^ 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.
  3. ^ 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" (PDF). Physical Review Letters. 50 (25): 2024–2027. Bibcode:1983PhRvL..50.2024D. doi:10.1103/PhysRevLett.50.2024. hdl:11370/e3946f6b-8acb-4e0a-80cf-735506203f25.

Further reading

[edit]


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