Electronic and magnetic properties of Co2Fe(Ga1−xSix) and Co2Fe(Al1−ySiy) Heusler alloys with high Curie temperature

We investigate the electronic and magnetic properties of Co2Fe(Ga1−xSix) and Co2Fe(Al1−ySiy) alloys using first-principles density functional theory based method. With increasing concentration of Si, lattice constant decreases linearly whereas bulk modulus and total magnetic moment increase. Electronic structure calculations show that the minority DOS exhibits a gap around Fermi level confirming the half-metallic character of the material for all the concentrations studied and the Fermi level can be shifted within the energy gap by changing the Si concentration. The Heisenberg exchange coupling parameters obtained from our calculations predict strong ferromagnetic coupling and high Curie temperatures, which is in accord with the experimental results.