Magnetic properties of praseodymium ions in Na2O-Pr2O3-SiO2 glasses

Sodium praseodymium silicate glasses of nominal composition 0.3Na(2)O xPr(2)O(3) (0.7-x)SiO2, where 0 less than or equal to x less than or equal to 0.10, have been studied by magnetisation and X-ray photoelectron spectroscopy (XPS). The magnetisation data fail to collapse to a single curve in the M versus HIT representation for all values of x and the spread increases with x, indicating an increase in the magnetic exchange interaction. The M versus H data acquired at different temperatures have been fitted with a Brillouin function by refining the number of Pr3+ ions in each glass sample. It was found that most of the Pr ions are in Pr3+ valence state and only a small fraction (less than or equal to 5%) in the Pr4+ state. Analysis of the XPS line shape indicates only the presence of Pr3+ ions in these glasses. (C) 2002 Elsevier Science B.V. All rights reserved.