Magnetic phase stability and spin-dependent transport in CeNi₄M (M=Sc, Ti, V, Cr, Mn, Fe, and Co): First-principles study

Using first-principles density functional calculations, the structural, magnetic, and spin-dependent transport properties of a set of intermetallic compounds CeNi₄M (M=Sc-Co) are investigated. All the compounds are considered to be in the orthorhombic phase, in which a transition metal atom M substitutes for one of the Ni atoms in the parent hexagonal CeNi₅ structure. The optimized lattice constants are shown to be in good agreement with the corresponding experimental data. The volume of CeNi₄M turns out to decrease with changing the M component from Sc to Co. Our calculations reveal that the ferromagnetic state is energetically more favorable for the compounds with M=Sc, Mn, Fe, and Co, while for CeNi₄Cr, the structure is found to be antiferromagnetic. Except for CeNi₄Sc, the magnetism in these compounds originates mainly from M atoms. The ferromagnetic coupling is mediated through the indirect d-d and d-f exchange interactions. The spin-dependent transport calculations show that the spin polarization in the diffusive regime is significantly higher than that in the ballistic one for these intermetallic compounds.