Synthesis and characterization of (Ba (1.6-3/2X) Sr2.4Na2Nb10O30: xHo3+) ferroelectric nanomaterials by solid state reaction routes for device applications

Abstract

Barium Strontium Sodium Niobate (Ba (1.6-3/2X)Sr2.4Na2Nb10O30:xHo3+) tungsten bronze structured ferroelectrics nanomaterial synthesized by conventional solid state reaction route is investigated. The X-ray diffraction (XRD), the scanning electron spectroscopy (SEM), energy dispersive x-ray spectroscopy (EDS), Fourier transform-infrared spectroscopy (FTIR) and UV–Vis Spectroscopy were used to study the structure, surface morphology/microstructure, elemental composition/mapping, functional groups identification and absorption, respectively. The XRD pattern revealed Tetragonal Tungsten Bronze structured crystallite phase that matches with the JCPDS card number -00-039-1453 having space group of p4bm and lattice parameters of a = 12.33 Å, b = 12.33 Å and c = 3.93 Å. The average crystallite size of the synthesized samples obtained at the prominent peak (311) for position/2ϴ = 32.320 is 67.52 nm. The SEM images showed that surface microstructures have random and nearly uniform distribution of nanoparticles with different shapes and size on the surface. Moreover, less porous surface microstructure was obtained and it is promising for enhancing ferroelectric properties. EDS analysis confirmed the presence of all the constituent elements with their proportional atomic and molecular weight ratios. For the pure metal oxide, the FTIR results showed the bond vibration mode at wavenumber of 540.60 cm−1, having only single collective metal oxide intense peak without impurities. For Ho3+ concentration corresponding to 0.05 and 0.10 %, additional peaks were observed at 429.92 cm−1 and 415.77 cm−1, respectively, confirming the existence of Ho–O bond vibration modes. The UV–vis results show that the absorption edges of all samples are at the same wavelength region (approximately 205 nm). Moreover, it was observed that the optimum absorption intensity was obtained for 0.03 % Ho3+ ions concentration.