First-principles studies on the structural, electronic and mechanical properties of L1_o and L1₂ Fe_xPt_1-x alloys

Bimetallic Fe_xPt_1-x alloys with the L1₀ and L1₂ structures have recently gained a lot of consideration in practical applications for solid-state devices, storage of ultra-high density magnetic data and biomedicine. This is due to their high magnetic and magnetocrystalline anisotropy, density, and coercivity. In order to gain knowledge on the structural, electronic and mechanical properties of the cubic and tetragonal Fe_xPt_1-x alloys, we have calculated their equilibrium lattice constants, density of states, and elastic constants at 0 K, employing first-principles calculations. The calculated equilibrium lattice constants were found to be in good agreement with the experimental data to within 3 %. All independent elastic constants satisfy the necessary stability conditions for both cubic and tetragonal systems, suggesting mechanical stability. The shear anisotropic factors predict that the tetragonal Fe_xPt_1-x crystals are highly anisotropic along the {001} plane than {100}. Moreover, the percentage of bulk (A_B) and shear (A_G) anisotropies revealed completely isotropic systems in the bulk and slightly anisotropic in shear modulus. (paper)