Structural, morphological and dielectric properties of ErNbO4 prepared by the sol-gel method. (November 2020)

• Record Type: Journal Article
• Authors: Devesa, S.; Teixeira, S. Soreto; Rooney, A.P.; Graça, M.P.; Cooper, D.; Costa, L.C.
• Is Part Of: Journal of physics and chemistry of solids. Volume 146(2020)
• Publication Date: 2020-11
• Subjects: Ceramics -- Sol-gel -- Rare-earth orthoniobates -- Microwave -- Dielectric properties; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2020.109619
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: In this work, ErNbO4 samples were prepared using the sol-gel method, through the citrate route, and heat-treated at temperatures between 700 and 1600 °C. The structure was studied by X-ray diffraction and Raman spectroscopy. The crystallite size was estimated using the Rietveld refinement and the Sherrer's formula, presenting values from 31.27 to 86.65 nm and from 40.96 to 78.23 nm, respectively. The morphology was studied by scanning electron microscopy. The measurement of the complex permittivity was made using the small perturbation technique, with a cavity operating in TE105 mode, at resonant frequency of 2.7 GHz. The increase of the treatment temperature promoted the increase of the dielectric constant and the dielectric losses were still maintained with low values, allowing their potential application in electric storage devices. The dielectric constant of ErNbO4 in a zero porosity sample case was estimated and compared with the experimental values. Graphical abstract: Image 1 Highlights: ErNbO4 ceramic powders were successfully prepared by the sol-gel method. A relation between the crystallite size and the lattice strain estimated through the Rietveld analysis was established. The crystallite size of ErNbO4 was obtained by three methods, with results. The dielectric constant of the sample treated at 1600 °C is not much lower than the estimated value for ErNbO4 with zero porosity. The dielectric constant increases with the treatment temperature, without significant increases of the losses.