Structural refinement, Raman spectroscopy, optical and electrical properties of (Ba1−xSrx)MoO4 ceramics

Abstract

In this paper, structural refinement, Raman spectroscopy, optical and electrical properties of barium strontium molybdate [(Ba 1-x Sr x )MoO 4 ] ceramics with different (x) contents (x = 0; 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9; and 1) were synthesized by the solid state reaction method. These ceramics were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, and micro-Raman spectroscopy. The shape of the grains for these ceramics was observed by means of scanning electron microscopy (SEM) images. The optical properties were investigated using ultraviolet-visible (UV-Vis) absorption spectroscopy and photoluminescence (PL) measurements. The dielectric and ferroelectric properties were analyzed by permittivity (e r ), loss tangent (tan d) and polarization versus electric field (P-E) hysteresis loop. XRD patterns, Rietveld refinement, and micro-Raman spectra showed that all ceramics are monophasic with a scheelite-type tetragonal structure. A decreased of lattice parameters and unit cell volume was observed with the increase of Sr 2? ions into BaMoO 4 lattice. Rietveld data were employed to model the [BaO 8 ], [SrO 8 ] and [MoO 4 ] clusters in the tetragonal lattices. The SEM images indicate that increased x content promotes a decrease in the grain size and modifications in the shape. UV-Vis spectra indicated a decrease in the optical band gap values with an increase in x content in the (Ba 1-x Sr x )MoO 4 ceramics. PL emissions exhibit a non-linear behavior to increase or decrease with the increase of Sr 2? ions in the tetragonal lattices, when excited by a wavelength of 350 nm. The P-E decreases along with slim hysteresis loop towards higher Sr 2? ions concentration. These effects are correlated with decrease in lattice parameters and c/a ratio in this tetragonal lattice. The microwave dielectric constant and quality factor were measured using the method proposed by Hakki-Coleman. Temperature coefficient and quality factor of these materials were measured by vector network analyzer.

Dielectric and magnetic characteristics of Ca1−xMnxMoO4 (0 ≤ x ≤ 0.15) nanomaterials

“…Divalent metal molybdates with relatively large cations such as Ca 2+ , Sr 2+ , Ba 2+ and Pb 2+ (ionic radius above 99 pm) exist in scheelite-type structure (tetragonal symmetry, space group I4 1 /a ; Z  = 4) where molybdenum ions adopt tetrahedral coordination, while divalent metal ions represent an eight-coordinated position (Sczancoski et al 2008; Sczancoski et al 2009; Ghosh et al 2015). Generally, metal molybdates are obtained by conventional solid-state reaction method (Pawlikowska et al 2017; Piątkowska and Tomaszewicz 2016; Tomaszewicz et al 2016).…”

“…Metal molybdates form a wide and important class of inorganic materials that have a high application potential in various fields such as scintillator detectors, phosphors and electro-optic applications (Zhang et al 2015; Bavykina et al 2009; Zhou et al 2011; Danevich et al 2014; Belogurov et al 2005; Mikhailik et al 2007; Korzhik et al 2008; Lei and Yan 2008; Shivakumara et al 2015). Divalent metal molybdates with relatively large cations such as Ca 2+ , Sr 2+ , Ba 2+ and Pb 2+ (ionic radius above 99 pm) exist in scheelite-type structure (tetragonal symmetry, space group I4 1 /a ; Z = 4) where molybdenum ions adopt tetrahedral coordination, while divalent metal ions represent an eight-coordinated position (Sczancoski et al 2008; Sczancoski et al 2009; Ghosh et al 2015). Generally, metal molybdates are obtained by conventional solid-state reaction method (Pawlikowska et al 2017; Piątkowska and Tomaszewicz 2016; Tomaszewicz et al 2016).…”

Structural, vibrational and photoluminescence properties of Sr(1-x)PbxMoO4 solid solution synthesized by solid state reaction

“…Recently, photoluminescence properties in solid solutions Sr 1-x Pb x WO 4 , Ca 1-x Cd x WO 4 and Ba 1-x Sr x MoO 4 ceramics were analyzed as a function of the composition x [1][2][3]68]. The general aim was to better understand the role of substitution in the photoluminescence of tungstates and molybdates.…”