Fabrication and magnetic properties of anisotropic SmCo₃/Fe(Co) bulk nanocomposite magnets

For bulk SmCo₃ system hard-soft magnetic nanocomposites, it remains a challenge to fabricate an anisotropic magnet by forming a strong texture for the nanocrystalline SmCo₃ phase. In this paper, we report the fabrication of a bulk anisotropic SmCo₃/Fe(Co) nanocomposite magnet with a strong (00 l) texture for the SmCo₃ phase and a small grain size of 21 nm for the Fe(Co) phase. Good results were achieved by controlling the nucleation and growth of the nanocrystals from the amorphous matrix using large stress and strain. The synthesized magnet exhibited a high-energy product of 17.0 MGOe, which was 26% larger than the reported highest value of 13.5 MGOe for SmCo₃-based nanocomposites and 314% higher than 4.1 MGOe for the corresponding pure SmCo₃ magnets. Moreover, these magnets possessed small remanence and coercivity temperature coefficients of α = −0.018%/°C and β = −0.24%/°C, which were much lower than those α = −0.14%/°C and β = −0.31%/°C for pure SmCo₃ magnets and α = −0.073%/°C and β = −0.30%/°C for SmCo₃/Fe(Co) isotropic nanocomposite. These findings are an important step toward the practical application of the SmCo₃-based nanocomposite.