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Photoluminescence and EPR studies of Cr-doped hibonite (CaAl(12)O(19)) phosphors

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Title Photoluminescence and EPR studies of Cr-doped hibonite (CaAl(12)O(19)) phosphors
Creator Singh, Vijay
Chakradhar, R P S
Rao, J. L.
Kim, Dong-Kuk
Subject Physical Properties
Description 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.
Publisher Elsevier
Date 2008-11
Type Article
Format application/pdf
Identifier http://cgcri.csircentral.net/477/1/Solid_State_Sc_10_(2008)_1525%2D1532.pdf
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
Relation http://cgcri.csircentral.net/477/