Synthesis and investigation of properties of nanostructured cubic PMN ceramics for possible applications in electronics

The pure phase of Pb(Mg_1/3Nb_2/3)O₃ was synthesized by two-stage chemical process at 800 °C. Thermal analysis of precursors was done by TG-DSC. XRD, Raman spectroscopy, FESEM and HRTEM analyses were done to characterize synthesized material and also to observe the microstructure. XRD studies revealed the formation of pure crystalline PMN ceramics (JCPDS PDF# 00-081-0861) having crystallite size around 28 nm. The particle size was examined to be around 19 nm by HRTEM. The nanocrystalline PMN ceramics exhibited a bandgap around 3.28 eV using diffuse reflectance spectroscopy. Dielectric nature was inspected using impedance analyzer between 40 Hz and 110 MHz. Dielectric constant ( \({\epsilon}_{r}\)) and \({\text{tan}}\delta\) were investigated where unusual negative values of \({\epsilon}_{r}\)were observed beyond 41.26 MHz. A peak in \({\text{tan}}\delta\) near 41.26 MHz was also obtained.