High-performance magnets based on Sm2Fe17

CMI researchers at Oak Ridge National Laboratory conducted the research for this highlight

Achievement
Theoretical calculations demonstrate that alloying with Cobalt  and Aluminum in Sm₂Fe₁₇ results in low-cost permanent magnet materials with excellent intrinsic properties.

Significance and impact
We propose a magnet based predominantly on Iron with low Cobalt content  (~15 % Co in Fe sublattice) and relatively inexpensive Samarium, with potential BH_max in the 20-30 MG-Oe range. 

Details and next steps

• First principles calculations demonstrated that Sm₂(Fe_1-xCox)₁₄Al₃ is uniaxial with magnetic anisotropy energy ~8 MJ/m3 in range of Cobalt concentrations 13-18% (top figure).
• The calculated magnetization at 13% Co substitution is 1.01 T.
• Substitution of Cobalt into Sm₂Fe₁₆Al results in even larger uniaxial anisotropy in all range of Co concentrations.
• Co substitution also increases Curie point significantly.