High Curie temperature of Ce-Fe-Si compounds with ThMn12 structure

We report the discovery of ternary CeFe12−xSix compounds possessing the ThMn12 structure. The samples were prepared by melt spinning followed by annealing. In contrast to other known Ce-Fe-based binary and ternary compounds, CeFe12−xSix compounds exhibit exceptionally high Curie temperatures whose values increase with added Si substitution. The highest Tc = 583 K in CeFe10Si2 rivals that of the well-established Nd2Fe14B compound. We ascribe the Tc behavior to a combination of Si-induced 3d band structure changes and partial Ce3+ stabilization.