Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7921493 | Materials Chemistry and Physics | 2018 | 35 Pages |
Abstract
In this work, we report on the structural, morphological, optical, dielectric and magnetic properties of undoped and Cr doped KNbO3 (KNb1-xCrxO3; xâ¯=â¯0.0, 0.01, 0.03 and 0.05â¯mol.%) synthesized at 900â¯Â°C by solid state reaction method. X-ray diffraction analysis showed the formation of single phase KNbO3 with the orthorhombic structure. Further, the Rietveld refinement analysis revealed that no impurity or secondary phase formation related to the Cr doping. The crystallite size of KNb1-xCrxO3 varies between 553â¯nm and 948â¯nm. All the characteristic Raman phonon modes of KNb1-xCrxO3 confirmed the formation of compound with the orthorhombic structure. The presence of K, Nb, O and Cr elements and a shift in binding energy of Nb and O was observed by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy analyses, respectively. Surface morphology of KNb1-xCrxO3 samples exhibit different morphologies, namely rods, cubes and micro edges. Diffuse reflectance spectra revealed that band gap of KNb1-xCrxO3 ceramics decreases with increasing Cr doping level. The photoluminescence emission peaks at â¼410-492â¯nm (blue) and 520â¯nm (green) indicate the oxygen vacancies present in the sample. A high coercivity (593â¯Oe) and saturation magnetization (0.021 emu gâ1) is obtained for 0.03â¯mol.% of Cr doping. The dielectric permittivity was enhanced with the increase of Cr doping concentration in KNbO3 matrix.
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Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
S. Raja, R. Ramesh Babu, K. Ramamurthi, K. Sethuraman,