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 abs orption studies for Mn2+ ions in praseodymium calcium manganese phosphate g lasses. 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 s tructure 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 ef fects 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 increas e in temperature whereas the linewidths are found to be independent of temp erature. As temperature is increased small fluctuations in hyperfine splitt ing are observed. From the optical absorption spectrum, the crystal field p arameters 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 Kluwe r Academic Publishers.