Effect of Ce3+ ion on structural, spectroscopic and dielectric enhancement of NdPO4 nanoparticles synthesized by wet chemical route

Abstract Pure and cerium mixed neodymium orthophosphate was synthesized as nanoparticles via wet chemical co-precipitation technique. Powder X-ray diffraction (PXRD) study suggests that the average crystallite size and X-ray density decreases with the mixing of cerium in neodymium orthophosphate. Scanning electron microscope (SEM) and transmission electron microscope (TEM) studies revealed spherical morphology for neodymium orthophosphate but when cerium is mixed the morphology changes into rectangular platelet, like nanorods. Fourier transform infrared (FTIR) spectroscopy signifies slightly shifting of bands towards lower wave number and the force constant were also calculated. Thermal analysis suggests that the material get stabilized after 425 °C and structural phase transition was seen above 800 °C. Optical absorption spectrum give various absorption bands corresponding to each wavelength revealing transitions of Nd 3+ and Ce 3+ present in the UV-VIS region and optical band gap energy decreases from 3.3 to 2.4 eV. Mixing of cerium in neodymium orthophosphate enhances the value of dielectric constant and decreases the transition temperature. The value of exponent ‘n’ suggest that in neodymium orthophosphate, conduction is through hopping mechanism but for cerium neodymium orthophosphate conduction correspond to long range diffusion of ions.