Coercivity and magnetization reversal mechanism in Sm2Co17 nano-flakes prepared by surfactant-assisted ball milling

The magnetization reversal process in Sm2(Co0.87Fe0.09Ti0.04)17 nano-flakes prepared by surfactant-assisted ball milling (SABM) was systematically studied. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the phase composition and morphology of the nano-flakes, respectively. XRD results show the strong [00l] texture in the magnetically aligned nano-flakes. The openness in the recoil loops of the aligned nano-flakes exhibits a large peak compared to the un-aligned flakes, which suggests the aligned nano-flakes have a strong exchange coupling interaction. Moreover, Henkel plots also revealed that the aligned nano-flakes possess a stronger exchange interaction than the un-aligned ones. The minor loops and initial magnetization curves revealed that the coercivity is controlled by both the nucleation of the magnetic domain and the pinning of domain wall movement. The value of the micro-structural parameter αKαφ is less than 0.3, which implies the coercivity mechanism is a mixture of nucleation and domain wall pinning.