Electronic and phonon properties of the full-Heusler alloys X2YAl (X = Co, Fe and Y = Cr, Sc): a density functional theory study


Arikan N., Iyigor A., Candan A., Ugur Ş. , Charifi Z., Baaziz H., ...More

JOURNAL OF MATERIALS SCIENCE, vol.49, no.12, pp.4180-4190, 2014 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 49 Issue: 12
  • Publication Date: 2014
  • Doi Number: 10.1007/s10853-014-8113-7
  • Title of Journal : JOURNAL OF MATERIALS SCIENCE
  • Page Numbers: pp.4180-4190

Abstract

First-principle calculations have been carried out on the structural, electronic, elastic, and phonon properties of the full-Heusler alloys X2YAl (X = Co, Fe and Y = Cr, Sc). The calculations predict that the Fe2CrAl and Co2CrAl are half-metallic ferromagnets at the equilibrium lattice constant with a minority-spin energy gap of 0.2912 and 0.668 eV, respectively. Fe2ScAl exhibit a gap in the majority density of states, with a few states at the Fermi level and about 0.217 states eV(-1), unlike the other Heusler compounds; due to this, it is considered a false half metal, and Co2ScAl is considered a non-magnetic compound. The elastic constants were derived from the slopes of the acoustic branches in the phonon-dispersion curve. The calculated lattice constants, bulk modulus, and first-order pressure derivative of the bulk modulus are reported for the L2(1) structure and compared with previous values. Phonon-dispersion curves were obtained using the first-principle linear-response approach of the density-functional perturbation theory. The specific heat capacity at a constant volume C (V) of X2YAl (X = Co, Fe and Y = Cr, Sc) alloys is calculated and discussed.