Magnetism: the driving force of order in CoPt, a first-principles study

• Published in: Journal of physics. Condensed matter Vol. 25; no. 5; p. 056005
• Main Authors: Karoui, S, Amara, H, Legrand, B, Ducastelle, F
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 06.02.2013; Institute of Physics
• Subjects: Cobalt base alloys; Cobalt compounds; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Intermetallics; Magnetic properties and materials; Magnetism; Mathematical analysis; Order disorder; Physics; Platinum compounds; Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.); Tetragonal lattices; Magnetic ordering; Ordered alloy; Platinum alloys; PAW calculation; Equiatomic alloy; Electronic density of states; Tight binding approximation; Magnetic anisotropy; Density functional method; Ordering; Ferromagnetism; Ab initio calculations; Heat of formation; Cobalt alloys
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/25/5/056005

CoPt equiatomic alloy orders according to the tetragonal L10 structure which favors strong magnetic anisotropy. Conversely, magnetism can influence the chemical ordering. We present here ab initio calculations of the stability of the L10 and L12 structures of Co-Pt alloys in their paramagnetic and ferromagnetic states. They show that magnetism strongly reinforces the ordering tendencies in this system. A simple tight-binding analysis allows us to account for this behavior in terms of some pertinent parameters.