Abstract
In this study, we investigated the structural, electronic and magnetic properties of new quaternary Heusler alloys CoX'YP (X' = Cr and Fe) using the accurate full-potential linearised augmented plane waves with local orbitals (FP-LAPW + lo) under the framework of the density functional theory (DFT) and the WIEN2k package. The generalised gradient approximation (GGA) is chosen to treat the exchange-correlation (XC) energy. The structural properties of the presented alloys are investigated in order to determine their structural parameters at equilibrium, such as: the lattice constant (a
0
), the bulk modulus (B
0
) and its first pressure derivative (B'). The structural stability of the CoCrYP and CoFeYP alloys is found in Y-type (I) structure, while their magnetic stability is reported in ferromagnetic phase. The electronic properties of the studied materials show the complete half-metallic character. The magnetic properties reveal that the total magnetic moment of the two alloys is found in integer value, obeying the Slater-Pauling rule. Furthermore, the calculated local magnetic moments of Co and X' atoms are found with opposite signs, confirming the ferrimagnetic coupling within these compounds. According to the electronic and magnetic results found in this approach, we conclude that the compounds CoCrYP and CoFeYP are full half-metallic ferromagnetic materials.