CMI researchers at Oak Ridge National Laboratory conducted the research for this highlight
Fully relativistic theoretical calculations demonstrate that significant magnetic anisotropy is not necessarily associated with presence of rare-earth metals suggesting a possible direction to increase Tc demonstrated.
Significance and impact
In a contrast to critical REE based magnets YCo5 and likely LaCo5 the source magnetic anisotropy energy (MAE) is the 3d-state of Co. It is of principal importance to produce a permanent magnet without critical REE.
Details and next steps
- Calculations reproduce uniaxial magnetic anisotropy in YCo5 with magnetic anisotropy energy ~8 MJ/m3 (see table).
- Substitution of Y by Sc or Al (both 3 valence electrons metals) reduces MAE but keeps it sizable, indicating the source of MAE is the 3d transition metal.
- The substitution of Co with transition metal with smaller number of valence electrons results in increase of Curie temperature (see Figure).