The effect of cobalt-sublattice disorder on spin polarisation in CoFeMnSi heusler alloys

TY - JOUR

T1 - The effect of cobalt-sublattice disorder on spin polarisation in CoFeMnSi heusler alloys

AU - Hasnip, P.J.

AU - Loach, C.H.

AU - Smith, Joseph H.

AU - Probert, M.I.J.

AU - Gilks, D.

AU - Sizeland, J.

AU - Lari, Leonardo

AU - Sagar, James

AU - Yoshida, K.

AU - Oogane, M.

AU - Hirohata, A.

AU - Lazarov, V.K.

PY - 2014

Y1 - 2014

N2 - In this work we present a theoretical study of the effect of disorder on spin polarisation at the Fermi level, and the disorder formation energies for CoFeMnSi (CFMS) alloys. The electronic calculations are based on density functional theory with a Hubbard U term. Chemical disorders studied consist of swapping Co with Fe/Mn and Co with Si; in all cases we found these are detrimental for spin polarisation, i.e., the spin polarisation not only decreases in magnitude, but also can change sign depending on the particular disorder. Formation energy calculation shows that Co-Si disorder has higher energies of formation in CFMS compared to CoMnSi and CoFeSi, with maximum values occurring for x in the range 0.5-0.75. Cross-sectional structural studies of reference CoMnSi, CoFeMnSi, and CoFeSi by Z-contrast scanning transmission electron microscopy are in qualitative agreement with total energy calculations of the disordered structures.

AB - In this work we present a theoretical study of the effect of disorder on spin polarisation at the Fermi level, and the disorder formation energies for CoFeMnSi (CFMS) alloys. The electronic calculations are based on density functional theory with a Hubbard U term. Chemical disorders studied consist of swapping Co with Fe/Mn and Co with Si; in all cases we found these are detrimental for spin polarisation, i.e., the spin polarisation not only decreases in magnitude, but also can change sign depending on the particular disorder. Formation energy calculation shows that Co-Si disorder has higher energies of formation in CFMS compared to CoMnSi and CoFeSi, with maximum values occurring for x in the range 0.5-0.75. Cross-sectional structural studies of reference CoMnSi, CoFeMnSi, and CoFeSi by Z-contrast scanning transmission electron microscopy are in qualitative agreement with total energy calculations of the disordered structures.

UR - http://www.scopus.com/inward/record.url?scp=84897033191&partnerID=8YFLogxK

U2 - 10.3390/ma7031473

DO - 10.3390/ma7031473

M3 - Article

AN - SCOPUS:84897033191

VL - 7

SP - 1473

EP - 1482

JO - Materials

JF - Materials

IS - 3

ER -