Structural stability and magnetic properties of Ni nanoparticles with an in situ formed surface stabilization layer of graphitic-carbon

Abstract

Finely dispersed spherical-shaped Ni nanoparticles, surface stabilized by a thin layer of in situ formed graphitic-carbon, were synthesized by a simple process involving heat-treatment of a complex precursor of Ni2+-poly-vinyl alcohol (PVA)-sucrose in Ar atmosphere at selected temperatures in the range of 400–600°C. The structural and compositional properties of the Ni nanoparticles were analyzed with X-ray diffraction (XRD), thermal analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). All the samples showed stable face-centered cubic (fcc) structure of Ni (Fm3m space group). Microstructural analysis disclosed the narrow size distribution of the Ni nanoparticles. The surface structure of the nanoparticles was evaluated by Raman and XPS techniques. The surface layer of graphitic-carbon ensures the structural stability of the nanoparticles even at a high temperature of 1200°C. The magnetic properties of the samples were analyzed at room-temperature with a vibrating sample magnetometer (VSM).