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Title: <span style="font-size:15.0pt;mso-bidi-font-size:16.0pt;mso-bidi-font-weight:bold" lang="EN-US">Effect of crystallite size on electron spin resonance of Gd<sup>3+</sup> and luminescence of Eu<sup>3+</sup> doped in La<sub>6</sub>WO<sub>12</sub> </span>
Authors: Devi, V Rama
Kumar, B Vijaya
Velchuri, Radha
Suresh, Palla
Ravi, G
Vithal, M
Keywords: Sol-gel
Powder XRD
Crystallite size
Issue Date: Jun-2012
Publisher: NISCAIR-CSIR, India
Abstract: Nano-sized Eu<sup>3+</sup> and Gd<sup>3+</sup> doped lanthanum tungstates of composition La<sub>6-x</sub>Ln<sub>x</sub>WO<sub>12</sub> (Ln = Eu, Gd; 0 ≤ x ≤ 0.2) are prepared by sol-gel complexation method. These samples are characterized by powder X-ray diffraction (XRD). The average crystallite size is calculated from the XRD using Scherer’s equation. The electron spin resonance (ESR) spectrum of Gd<sup>3+</sup> doped lanthanum tungstate (La<sub>6</sub>WO<sub>12</sub>) gives characteristic “U” type spectrum. The luminescence spectrum of Eu<sup>3+</sup> doped La<sub>6</sub>WO<sub>12</sub> gives characteristic <sup>5</sup>D<sub>0</sub>→<sup>7</sup>F<sub>n</sub> (<i style="mso-bidi-font-style:normal">n</i> = 0 to 4) bands due to trivalent europium ions. The intensity of <sup>5</sup>D<sub>0</sub>→<sup>7</sup>F<sub>2</sub> transition decreases with increase in the sintering temperature due to depletion of surface Eu<sup>3+</sup> ions. The intensity of <sup>5</sup>D<sub>0</sub>→<sup>7</sup>F<sub>2</sub> sintered at 700°C has highest intensity and may have laser applications.
Description: 204-208
ISSN: 0975-1017 (Online); 0971-4588 (Print)
Appears in Collections:IJEMS Vol.19(3) [June 2012]

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