Ab initio studies of disorder in the full Heusler alloy Co FeMnSi

TY - JOUR

T1 - Ab initio studies of disorder in the full Heusler alloy Co FeMnSi

AU - Hasnip, P.J.

AU - Smith, J.H.

AU - Lazarov, V.K.

PY - 2013/5/7

Y1 - 2013/5/7

N2 - Co-based full Heusler alloys have been predicted to be half-metals, with 100 spin polarisation at the Fermi level, yet this has yet to be realised in practice. Heusler thin-films often exhibit a degree of atomic disorder, and this is believed to be one cause of the low magnetoresistance in Heusler-based spin valves devices. We present an ab initio density functional theory U investigation into the effect of disorder on the electronic properties of CoFeMnSi. It is found that the half-metallicity depends strongly on the kind of disorder present, with low or even reversed spin-polarisation when the Co sublattice mixes with either the Fe/Mn or Si sublattice, but keeps the high spin polarisation when the Mn/Fe and Si sublattices are mixed. Calculations of the formation energy show that this latter kind of disorder is by far the most likely to occur, an encouraging result which means that it may not be necessary to produce perfectly ordered Heusler alloys in order to achieve 100 spin polarisation.

AB - Co-based full Heusler alloys have been predicted to be half-metals, with 100 spin polarisation at the Fermi level, yet this has yet to be realised in practice. Heusler thin-films often exhibit a degree of atomic disorder, and this is believed to be one cause of the low magnetoresistance in Heusler-based spin valves devices. We present an ab initio density functional theory U investigation into the effect of disorder on the electronic properties of CoFeMnSi. It is found that the half-metallicity depends strongly on the kind of disorder present, with low or even reversed spin-polarisation when the Co sublattice mixes with either the Fe/Mn or Si sublattice, but keeps the high spin polarisation when the Mn/Fe and Si sublattices are mixed. Calculations of the formation energy show that this latter kind of disorder is by far the most likely to occur, an encouraging result which means that it may not be necessary to produce perfectly ordered Heusler alloys in order to achieve 100 spin polarisation.

UR - http://www.scopus.com/inward/record.url?scp=84877765075&partnerID=8YFLogxK

U2 - 10.1063/1.4801745

DO - 10.1063/1.4801745

M3 - Article

AN - SCOPUS:84877765075

SN - 0021-8979

VL - 113

JO - Journal of Applied Physics

JF - Journal of Applied Physics

IS - 17

M1 - 17B106

ER -