Kesavulu, C R and Chakradhar, R P S and Muralidhara, R S and Rao, J L and Anavekar, R V (2010) EPR, optical absorption and photoluminescence properties of Cr(3+) ions in lithium borophosphate glasses. Journal of Alloys and Compounds, 496 (1-2). pp. 75-80. ISSN 0925-8388

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Electron paramagnetic resonance (EPR), optical absorption and photoluminescence studies of Cr(3+) ions in lithium borophosphate glasses have been studied. The EPR spectra exhibit two resonance signals with effective g values at g = 4.56 and g = 1.96. These resonance signals are attributed to isolated Cr(3+) ions and exchange coupled Cr(3+) pairs, respectively. The EPR spectra have also been studied at various low temperatures. The population of spin levels (N) participating at resonance signal g = 1.96 has been calculated as a function of temperature. The spin-population (N) is found to be increasing with decrease in temperature. The magnetic susceptibility (chi) was calculated from the EPR data. It is observed that as temperature decreases, chi increases in accordance with Curie-Weiss law. The exchange coupling constant J between Cr(3+) ions is calculated from the relative intensities of g = 1.96 resonance line at various temperatures. The optical absorption spectrum exhibits four bands characteristic of Cr(3+) ions in octahedral symmetry. From the optical absorption spectral data, the crystal field (Dq) and Racah parameters (B and C) have been evaluated. The luminescence spectrum exhibits a red emission peak, which is assigned to a transition from the upper (4)T(2g) (F) -> (4)A(2g) (F) ground state of Cr(3+) ions. The optical band gap is evaluated from the ultraviolet absorption edges. (C) 2010 Elsevier B.V. All rights reserved.

Item Type: Article
Uncontrolled Keywords: Cr3+; Electron paramagnetic resonance (EPR); Photoluminescence; Optical
Subjects: Glass
Depositing User: Bidhan Chaudhuri
Date Deposited: 13 Feb 2012 10:36
Last Modified: 13 Feb 2012 10:36

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