Synthesis and characterization of M3V2O8 (M = Ca, Sr and Ba) by a solid-state metathesis approach

Abstract

A solid-state metathesis approach initiated by microwave energy has been successfully applied for the synthesis of orthovanadates, M 3 V 2 O 8 (M = Ca, Sr, and Ba). The structural, vibrational, thermal, optical and chemical properties of synthesized powders are determined by powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, magnetic property measurements and diffused reflectance spectra in the UV-VIS range. The direct bandgap of the synthesized materials was found to be 3⋅55 ± 0⋅2 eV, 3⋅75 ± 0⋅2 eV and 3⋅57 ± 0⋅2 eV for Ca 3 V 2 O 8 , Sr 3 V 2 O 8 and Ba 3 V 2 O 8 , respectively.

Pyroelectric Response and Conduction Mechanism in Highly Crystallized Ferroelectric Sr3(VO4)2 Ceramic

“…81-1844. 15,26 This study also suggests that the solid-state reaction technique is suitable for growth of Sr 3 V 2 O 8 crystallites with the development of some high-intensity peaks from the (1 0 5), (1 1 0), and (2 0 5) planes in the preferred orientations. The lattice parameters of the selected unit cell were refined using the leastsquares subroutine of the standard computer software POWD, 27 yielding values of a = 5.6179(4) Å and c = 20.0854(3) Å , where the number in parenthesis denotes the standard deviation of the unit cell parameter.…”

“…The refined unit cell parameters with the proposed crystal structure (trigonal) of the sample agree well with previous reports. 15,26,28 The contributions from strain and other effects in the broadening of the XRD peaks and crystallite size calculation were ignored due to the use of a powder sample.…”

“…As a result, the palmierite structure is expected to be formed from that of the 9R polytypes. 15 Further study on this SrO-V 2 O 5 binary system (i.e., Sr 3 V 2 O 8 ) reveals that such compounds decompose at ambient atmosphere and temperature because of their compositional variation with experimental conditions. The study also reveals that the interlayer site of the Sr 2+ cation is half-occupied with a random distribution of vacancies.…”

“…The study also reveals that the interlayer site of the Sr 2+ cation is half-occupied with a random distribution of vacancies. The defect structure and the presence of V 4+ ions account for its high-temperature ferroelectric nature 15 and high electrical conductivity. 16,17 Detailed analysis of available literature reveals many potential applications of such metal orthovanadates, e.g., in the fabrication of luminescent lamp coatings, television tubes, flat-panel displays, microwave filters and antennas, etc.…”

“…16,17 Detailed analysis of available literature reveals many potential applications of such metal orthovanadates, e.g., in the fabrication of luminescent lamp coatings, television tubes, flat-panel displays, microwave filters and antennas, etc. [15][16][17][18][19][20][21][22] Grzechnik et al 18 reported that such vanadates show intense rare-earth-activated luminescence. Also, as reported by Umemura et al, 19 strontium orthovanadate is very useful for microwave applications, due to its low loss and excellent microwave dielectric properties.…”