Structural, microstructural, optical, and dielectric properties of Mn2+: Willemite Zn2SiO4 nanocomposites obtained by a sol-gel method

Autor: M. Ravi, S. Babu, B. Vengla Rao, B. Chandra Babu
Rok vydání: 2017
Předmět:
Zdroj: Journal of Molecular Structure. 1127:6-14
ISSN: 0022-2860
DOI: 10.1016/j.molstruc.2016.07.074
Popis: The synthesis of Zn 2 SiO 4 doped with Mn 2+ ions at different concentrations have been successfully achieved by a conventional sol–gel method. The structure and morphology of the obtained samples were characterized by XRD, FTIR, Raman spectroscopy, EDAX, and FE-SEM, TEM. The XRD results of Zn 2 SiO 4 samples with different Mn concentrations showed no obvious differences from the willemite structure. The SEM and TEM results showed the ceramic powders are nanometer sized spherical grains spherical forms and EDAX results confirmed the successful doping of Mn 2+ ions into Zn 2 SiO 4 matrix. The optical and dielectric properties of Mn 2+ ions doped Zn 2 SiO 4 show an appreciable difference between the levels of Mn 2+ doping. The luminescence spectra showed that 0.25mol% Mn 2+ in Zn 2 SiO 4 gives a maximum intensity a in the green emission corresponding to the 4 T 1 (4G) → 6 A 1 (6S) transition for tetrahedral-coordinated Mn 2+ (weak crystal field) and at higher levels of Mn 2+ doping the green band intensity decreases. The 0.25mol% Mn 2+ in Zn 2 SiO 4 also gives the highest ionic conductivity at 373 K. The dielectric constant ( e ′), loss tangent (tan δ) and AC conductivity (σ ac ) properties as the function of frequency have also been analyzed and those are strongly dependent on Mn ion concentrations.
Databáze: OpenAIRE
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