Eur. Phys. J. B (2016) 89: 267
https://doi.org/10.1140/epjb/e2016-70183-6

Regular Article

Ab-initio study of structural, elastic, thermal, electronic and magnetic properties of quaternary Heusler alloys CoMnCrZ (Z = Al, As, Si, Ge)

¹ Condensed Matter and sustainable development Laboratory (LMCDD), University of Sidi Bel-Abbes, Sidi Bel-Abbes 22000, Algeria
² UCCS, CNRS-UMR 8181, Université d’Artois, Faculté des Sciences Jean Perrin, Rue Jean Souvraz, SP 18, 62307 Lens Cedex, France

^a e-mail: mohamediwalid@yahoo.fr

Received: 23 March 2016
Received in final form: 1 October 2016
Published online: 7 December 2016

Abstract

First-principles approach is used to study the structural, electronic and magnetic properties of CoMnCrZ (Z = Al, Si, Ge and As) quaternary Heusler compounds, using full-potential linearized augmented plane wave (FP-LAPW) scheme within the generalized gradient approximation (GGA). The computed equilibrium lattice parameters agree well with the available theoretical data. The obtained negative formation energy shows that CoMnCrZ (Z = Al, Si, Ge, As) compounds have strong structural stability. The elastic constants C_ij are calculated using the total energy variation with strain technique. The polycrystalline elastic moduli (namely: the shear modulus, Young’s modulus, Poisson’s ratio, sound velocities, Debye temperature and melting temperature were derived from the obtained single-crystal elastic constants. The ductility mechanism for the studied compounds is discussed via the elastic constants C_ij. Our calculations with the GGA approximation predict that CoMnCrGe, CoMnCrAl, CoMnCrSi and CoMnCrAs are half-metallic ferrimagnets (HMFs) with a half-metallic gap E_HM of 0.03 eV, 0.19 eV, 0.34 eV and 0.50 eV for, respectively. We also find that the half-metallicity is maintained on a wide range of lattice constants.