Removing the surfactant of SmCo₅ nanoflakes via ligand-exchange and vacuum heat-treatment

The SmCo₅ nanoflakes covered with polyvinylpyrrolidone (PVP) surfactant are obtained via surfactant-assisted ball milling method and were treated by ligand-exchange and vacuum heat-treatment methods. No significant change in the phase structure and surface morphology of as-milled SmCo₅ nanoflakes was found upon those as confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis, respectively. Moreover, X-ray photoelectron spectroscopy (XPS) analysis revealed that the ligand-exchange and vacuum heat-treatment are effective techniques for removing the polyvinylpyrrolidone (PVP) surfactant from the surface of SmCo₅ nanoflakes. Meanwhile, the mechanism of coercivity is studied by the temperature dependence of demagnetization curves, which indicates that the magnetization reversal is controlled by co-existed mechanisms of pinning and nucleation.