Singh, Vijay and Chakradhar, R P S and Rao, J. L. and Kim, Dong-Kuk (2008) Photoluminescence and EPR studies of Cr-doped hibonite (CaAl(12)O(19)) phosphors. Solid State Sciences, 10 (11). pp. 1525-1532. ISSN 1293-2558

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Abstract

CaAl(12)O(19):Cr powder phosphors have been prepared at 500 degrees C in less than 5 min by a combustion method and characterized by XRD, FT-IR, SEM, EPR and photoluminescence techniques. The g values evaluated from EPR spectroscopy indicate that the site symmetry around Cr(3+) ions is distorted octahedral as Cr(3+) ions substitute for Al(3+) sites. The number of spins (N) participating in the resonance for g = 1.97 is measured as a function of temperature and the activation energy is calculated. The paramagnetic susceptibility (chi) is calculated from the EPR data at various temperatures. From the plot 1/chi versus T, the Curie constant (C) and Curie paramagnetic temperature (theta(p)) have been evaluated. The exchange coupling constant J between Cr(3+) ions has also been evaluated. The excitation spectrum exhibits two broad bands characteristic of Cr(3+) ions in octahedral symmetry. The crystal field and Racah parameters have been evaluated and discussed. (c) 2008 Elsevier Masson SAS. All rights reserved.

Item Type:	Article
Uncontrolled Keywords:	Photoluminescence; Electron paramagnetic resonance; Cr(3+) ions; Combustion; Phosphors
Subjects:	Physical Properties Glass
Divisions:	Glass
Depositing User:	Bula Ghosh
Date Deposited:	23 Jan 2012 06:31
Last Modified:	02 Mar 2012 11:10
URI:	http://cgcri.csircentral.net/id/eprint/477

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