Spin-polarized structural, electronic and magnetic properties of diluted magnetic semiconductors Ca0.75TM0.25O (TM = Fe, Co and Ni) in the rock salt (B1) phase

摘要

The structural, electronic and magnetic properties of the diluted magnetic semiconductors (DMSs) Ca0.75TM0.25O (TM = Fe, Co and Ni) were investigated in the rock salt (B1) phase using the full potential linearized augmented plan wave plus orbital (FP-L/APW+lo) method based on spinpolarized density functional theory (SDFT). The lattice constants, bulk modulii, spin-polarized band structures and total and local densities of states have been computed. We calculated the spin-exchange splitting energies ï????Ec and ï????Ev produced by Fe, Co and Ni-3d states and the results indicate that the effective potential for the minority spin is more attractive than that of the majority spin. The sÂ??d exchange constant ï??¡ 0 N (conduction band) and pÂ??d exchange constant ï??¢ 0 N (valence band) were calculated. The magnetic moment value per Fe, Co and Ni impurity atomis found to be 3.59, 2.59 and 1.59 ìB. The hybridization between Ca-p and TM-3d reduces the localmagnetic moment of TMand produces small local magnetic moment on the non magnetic Ca and O sites. The Fe, Co and Ni- 3d half-filled electrons have been treated as valence electrons and due to their hybridization, the ternary alloys Ca0.75TM0.25O (TM = Fe, Co and Ni) have well defined spin-up and spin-down band structures.