A study of electron paramagnetic resonance and optical absorption in calcium manganese phosphate glasses containing praseodymium

This paper reports on electron paramagnetic resonance (EPR) and optical absorption studies for Mn2+ ions in praseodymium calcium manganese phosphate glasses. The EPR spectra exhibit three resonance signals at g approximate to 2.0, g approximate to 3.3 and g approximate to 4.8. A six line hyperfine structure spectrum centered at g approximate to 2.0 has been observed in the EPR spectra of all the glasses at lower concentration of Mn2+ ions. The effects of the concentration of Mn2+ ions and praseodymium oxide on resonance signals have been studied. The temperature dependence of EPR signals were also studied. The intensity of the resonance signals decreases with increase in temperature whereas the linewidths are found to be independent of temperature. As temperature is increased small fluctuations in hyperfine splitting are observed. From the optical absorption spectrum, the crystal field parameters and optical band gap energy were evaluated. The optical band gap energy is found to depend quite sensitively on added manganese content. The theoretical values of optical basicity were also evaluated. (C) 2000 Kluwer Academic Publishers.