High Coercivity and Strong [00l] Crystallographic Texture in Sm(CoFeCuZr)_7.4 Nanoflakes Prepared by Surfactant‐Assisted Ball Milling

Abstract

Sm(Co0.61Fe0.21Cu0.13Zr0.05)7.4 nanoflakes are prepared by surfactant‐assisted ball milling from annealed ingots, and the ingots are synthesized by the arc‐melting process. The X‐ray diffraction (XRD) patterns of nanoflakes exhibit two hard magnetic phases: Sm2Co17 is the primary hard phase, which provides high saturation magnetization, and SmCo5 acts as a minor hard phase, presumably impeding the movement of magnetic domain walls, thereby increasing intrinsic coercivity. The high coercivity value of 7.2 kOe is achieved after 0.5 h ball milling. In addition, the XRD patterns of nanoflakes at different milling times show a strong [00l] crystallographic texture after the magnetic alignment. A remanence value of 1.03 T and a maximum energy product of 123 kJ m−3 achieve in 0.5 h milled nanoflakes. The aligned nanoflakes show strong anisotropic behavior with a degree of anisotropy value of 0.81. Henkel plots indicate the strong exchange coupling interaction in nanoflakes milled for 0.5 h. Based on the analysis of temperature‐dependent hysteresis loops and initial magnetization curves, the coercivity is controlled by the pinning of domain wall movement and the nucleation of the reverse domains.