Magnetic and optical properties and electron paramagnetic resonance of gadolinium-containingoxide glasses

Abstract

Magnetic susceptibility, electron paramagnetic resonance (EPR)and optical absorption have been studied in a glass system20La2O3–22Al2O3–23B2O3–35(SiO2+GeO2) with apart of La2O3 substituted by Gd2O3 in different concentrations. Positive Weiss constants have beenfound in more heavily doped glasses and ascribed to clustering ofGd3+ ions.Computer simulations of the EPR spectra show that the short-range ordering in the environment ofthe Gd3+ ions is well preserved. The relative distribution widths of the ligand coordinates are lessthan 2%. In the more heavily doped glasses the EPR spectra are superpositionsof signals arising from isolated ions and ferromagnetic clusters. The increase ofGd3+ concentration is shown to change substantially the strong optical absorption edgewhile only small changes of f–f absorption band characteristics are observed. Thisdifference is associated with the different effect of the Gd ion clustering on themechanisms of the strong absorption in the ultraviolet region and the f–f absorption.