Study on structural, magnetic properties of undoped and Ni doped CdS nanoparticles

We report here, structural, magnetic properties of undoped and Ni doped CdS (Ni: 10, 15, and 20 mol%) nanoparticles synthesized by a chemical method. The effect of Ni doping on these properties has been studied by energy dispersive analysis of X-rays (EDAX), X-ray diffractometer (XRD), Transmission electron microscope (TEM), Raman spectra, magnetic susceptibility measurement by the Gouy method and M–H and M–T plots by a vibrating sample magnetometer (VSM). The purity of samples was confirmed by EDAX whereas XRD revealed the cubic structure of all these samples. The calculated crystallite size by Scherrer׳s formula and Hall–Williamson plot lies between 3 and 6 nm, whereas the particle size determined by TEM lies between 2 and 6 nm for undoped and Ni doped CdS nanoparticles. From Raman spectra we could observe small shift in wave number with Ni doping in CdS which may be attributed to optical phonon confinement. Magnetic susceptibility measurement using the Gouy method has shown paramagnetic behavior of Ni doped CdS and diamagnetic behavior of undoped CdS nanoparticles. The M–H curves at 5 K and 300 K obtained using VSM showed paramagnetic behavior of Ni doped CdS nanoparticles whereas M–T curves at 10,000 Oe and 500 Oe magnetic field showed rapid increase in magnetization below 5 K temperature.