Novel exchange-coupled SmFe3/alpha-Fe nanocomposite magnets fabricated by magnetic annealing

作者：Li Liya^*; Yan A ru; Peng Hua xin; Luo Yang; Yi Jianhong; Peng Yuandong

来源：Journal of Magnetism and Magnetic Materials, 2015, 375: 143-147.

DOI：10.1016/j.jmmm.2014.09.064

• SmFe3/alpha-Fe nanocomposite magnet
• Exchange coupling
• Magnetic annealing

A new nanocomposite magnet containing exchange-coupled SmFe3 and alpha-Fe phases has been successfully fabricated via melt spinning followed by magnetic annealing at 450-470 degrees C for 10 min. These SmFe3/alpha-Fe magnets show remarkably high remanent ratio, M-r/M-s, up to 0.93 and display a smooth single-phase-like loop with excellent rectangularity. In comparison, the non-field treated ones exhibit much lower M-r/M-s values and show a distinctive kink in the demagnetization curve due to the decoupling of the nanograins. The Henkel plot and microstructural examination confirm that magnetic annealing leads to much stronger intergranular exchange coupling, which is attributed to the formation of a magnetic-field-induced microstructure consisting of the SmFe3 hard phase with diameters of 80-100 am and the alpha-Fe soft phase with size of about 3-8 nm. An enhanced energy product of 13.0 MGOe has been obtained in the ribbon magnetically annealed at 470 degrees C, which is about 60% higher than that of the ribbon annealed without a magnetic field.

• 单位
  中南大学; 1; 中国科学院