Thermodynamics and Magnetism of SmFe₁₂ Compound Doped with Zr, Ce, Co and Ni: An Ab Initio Study

Alloys that are Ni-doped, such as the (Sm1-yZry)(Fe1-xCox)(12) and (Ce0.5Sm0.5)Fe10Co2 systems, are studied because of their magnetic properties. The (Sm1-yZry)(Fe1-xCox)(11-z)Ti-z and (Ce.Sm-1-x(x))Fe9Co2Ti alloys are considered contenders for vastly effective permanent magnets because of their anisotropy field and Curie temperature. Ti can act as a stabilizer for the SmFe12 compound but substantially suppresses saturation magnetization. To maintain the saturation magnetization in the scope of 1.3-1.5 T, we propose substituting a particular quantity of Fe and Co in the (Sm1-yZry)(Fe1-xCox)(12) and (Ce0.5Sm0.5)Fe10Co2 alloys with Ni. By performing ab initio calculations, we show that Ni incorporation results in increased thermodynamic stability and, in contrast to Ti, has a parallel spin moment aligned to the moment of the SmFe12 compound and improves its saturation magnetization without affecting the anisotropy field or Curie temperature.