Preparation by chemical co-precipitation, spectral and electrical characteristics of neodymium orthophosphate nanoparticles

Nanoparticles of neodymium orthophosphate (NdPO4) were prepared through a facile wet co-precipitation technique. The X-ray diffraction (XRD) studies revealed the material belonging to monoclinic monazite phase with crystallite size of 30.8 nm. Scanning electron microscopic studies showed that the material was composed of a large number of agglomerated spherical particles having grain size of 92 nm. Thermogravimetric analysis suggested that the structural phase transition was seen above 800 °C. The spectroscopic investigations were carried out using Fourier transform infrared spectroscopy (FTIR). UV-VIS-NIR absorption spectrophotometer showed various transitions from the ground state 4I9/2 to various excited states within the 4f shell and the optical band gap came out to be 3.3 eV. The dielectric constant (ε′), dielectric loss (tan d) and ac conductivity ln(sac) were measured in the frequency range of 5 kHz to 1 MHz and in the temperature range of 40 to 500 °C. The dielectric measurement suggested that there was a shift in the value of transition temperature (Tc), thereby indicating relaxor behaviour of the material. The activation energy value decreased with increase in frequency, thereby suggesting the role of mixed ionic-polaronic conductivity.

Graphical abstractNdPO4 nanoparticles prepared by chemical co-precipitation technique along with scanning electron microscopy with EDAX (a) and optical band gap energy plot (b)Figure optionsDownload full-size imageDownload as PowerPoint slide