Structural and third order nonlinear optical properties of Gd doped NiWO4 nanostructures

We report the synthesis of Pure and Gd doped NiWO4 nanoparticles by chemical precipitation technique with excellent linear and nonlinear optical properties. The significant effects of Gd doping on optical, structural, morphological and magnetic properties have been investigated by UV-Vis spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Vibrating sample magnetometer (VSM) techniques. XRD pattern for pure and Gd doped NiWO4 demonstrates the wolframite monoclinic structure and the crystallite size decreases with increase in Gd concentration as confirmed by SEM. Magnetic hysteresis (MH) curves from the VSM measurement have shown excellent ferromagnetic nature of the nanostructures at room temperature. The nonlinear optical properties of NiWO4 nanoparticles investigated using Z-scan technique demonstrate that the nanoparticles with increasing Gd have shown excellent nonlinear optical behavior. The nanoparticles clearly exhibit a negative value of nonlinear refraction, which is attributed to the two photon absorption (2PA) and free carrier absorption.