EPR and optical absorption studies of Fe³⁺ ions in sodium borophosphate glasses

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• 作者：R.S. Muralidhara ; C.R. Kesavulu ; J.L. Rao ; R.V. Anavekar ; R.P.S. Chakradhar
• 关键词：A. Amorphous materials ; A. Glasses ; B. Chemical synthesis ; D. Electron paramagnetic resonance (EPR) ; D. Optical properties
• 刊名：Journal of Physics and Chemistry of Solids
• 出版年：2010
• 出版时间：December 2010
• 年：2010
• 卷：71
• 期：12
• 页码：1651-1655
• 全文大小：469 K

文摘

Electron paramagnetic resonance (EPR) and optical absorption spectral investigations have been carried out on Fe³⁺ ions doped sodium borophosphate glasses (NaH₂PO₄–B₂O₃–Fe₂O₃). The EPR spectra exhibit resonance signals with effective g values at g=2.02, g=4.2 and g=6.4. The resonance signal at g=4.2 is due to isolated Fe³⁺ ions in site with rhombic symmetry whereas the g=2.02 resonance is due to Fe³⁺ ions coupled by exchange interaction in a distorted octahedral environment. The EPR spectra at different temperatures (123–295 K) have also been studied. The intensity of the resonance signals decreases with increase in temperature whereas linewidth is found to be independent of temperature. The paramagnetic susceptibility (c7;) was calculated from the EPR data at various temperatures and the Curie constant (C) and paramagnetic Curie temperature (θ_p) have been evaluated from the 1/c7; versus T graph. The optical absorption spectrum exhibits bands characteristic of Fe³⁺ ions in octahedral symmetry. The crystal field parameter (Dq) and the Racah interelectronic repulsion parameters (B and C) have also been evaluated and discussed.