High-performance, cost-effective permanent nanomagnet: Microstructural and magnetic properties of Fe-substituted SmCo nanofiber

Abstract We propose the substitution of some Co atoms in SmCo nanofibers with earth-abundant Fe as a means to prepare low-cost magnets with enhanced intrinsic magnetic properties compared to those of pure SmCo. To investigate the effect of Fe substitution upon microstructural and magnetic properties, we synthesized SmCoFe nanofibers (150–200 nm diameter) having various degrees of Fe substitution (0, 5, 10, 20, and 40 at%) via electrospinning and subsequent reduction using CaH2. All Fe-substituted samples showed an enhancement in (BH)max as compared to their non-substituted counterpart. Interestingly, substituting appropriate amount of Fe for Co enabled simultaneous increase of Ms, Hci and thus (BH)max of the SmCo nanofibers, resulting from an effective exchange-coupling effect: Superior Hci (about 7375 Oe) and a (BH)max (about 13.17 MG·Oe) over 153% that of non-substituted SmCo nanofibers were obtained in the 10 at% Fe-substituted sample. This work describes the synthesis of SmCoFe ternary magnetic nanofibers and elucidates the phase formation mechanism and the effect of Fe substitution in optimizing magnetic performance. This understanding can be extended to the synthesis of other SmCo phases having different chemical compositions and may enable access to a path far beyond the limitations of traditional magnetic materials.