Electrical and magnetic properties of lead nickel titanate synthesized by sol-gel method and microwave processing

The Pb1-xNixTiO3 (x = 0.0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0) nanoparticles are synthesized by sol-gel method and microwave sintering technique. Samples calcinated at 730 °C exhibit pseudo-cubic crystal structure, further sintering at 1000 °C the samples exhibited tetragonal structure except x = 0.8. The crystallite size is found to be 47-39 nm. Fourier Transfer-Infra Red studies confirm the PbTiO, TiO and NiO bond formation of prepared samples. The optical excitation spectrum reveals that the samples have direct allowed energy bandgap values of 2.81 to 2.82 eV. Synthesized samples particle size found to be 1 μm to 31 nm from High-Resolution Scanning Electron Microscope analysis. The particle size is found to be decreasing on increasing the nickel concentration. X-ray powder diffraction and electron microscope profiles confirmed single phase behaviour of the compounds in lower concentration of nickel. The prepared compounds show nearly spherical shape morphology with an average particle size of 1 μm to 31 nm which is close to crystallite size determined from the XRPD. The temperature dependent dielectric constant (ε) measurement show low values at room temperature and were nominally changes with increasing temperature upto 350 K. The ac electrical study of synthesized samples confirms the negative temperature coefficient of resistance and thermally activated charge carriers are responsible for the high-temperature behaviour. At room temperature prepared samples exhibited superparamagnetic nature. The saturation magnetization (Ms) and coercivity values are found to be 0.08-15.9 emu/g and 236-195 Oe at 15 kG field strength.