Half-metal: Difference between revisions

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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]

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.

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

^ ^a ^b Coey, J.M.D.; Venkatesan, M. (2002). "Half-metallic ferromagnetism: Example of CrO2". Journal of Applied Physics. 91 (10): 8345–8350. Bibcode:2002JAP....91.8345C. doi:10.1063/1.1447879.

Son, Y.W.; Cohen, M.L.; Louie, S.G. (2006). Half-metallic graphene nanoribbons Nature 444: 347-349. doi:10.1038/nature05180
http://www-users.york.ac.uk/~ah566/research/half_metals.html
http://www.tcd.ie/Physics/People/Michael.Coey/oxsen/newsletter/january98/halfmeta.htm

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[COEY02-1] Coey, J.M.D.; Venkatesan, M. (2002). "Half-metallic ferromagnetism: Example of CrO2". Journal of Applied Physics. 91 (10): 8345–8350. Bibcode:2002JAP....91.8345C. doi:10.1063/1.1447879.

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+{{distinguish|semi-metal}}
 [[Image:Half metar sattar.JPG|thumb|Electronic structure of a half-metal that 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|oxides]], [[Sulfide|sulfides]], or [[Heusler alloy|Heusler alloys]].<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=8345–8350 |doi=10.1063/1.1447879|bibcode = 2002JAP....91.8345C }}</ref> A half-metal should not be confused with a [[semi-metal]].
+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|oxides]], [[Sulfide|sulfides]], or [[Heusler alloy|Heusler alloys]].<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=8345–8350 |doi=10.1063/1.1447879|bibcode = 2002JAP....91.8345C }}</ref>
 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.