The Network Formers Role of Gadolinium(III) Ions in Some Zinc-Borate Glass Ceramics

EPR and magnetic susceptibility measurements were performed on glass ceramics from the (Gd2O3)(x)(B2O3)((60-x))center dot(ZnO)(40) system, with 0 <= x <= 15 mol%, in order to determine the role of gadolinium ions on structural and magnetic properties. At low Gd2O3 contents (x <= 1 mol%) the EPR spectra show four resonance lines with effective g-values of similar to 6, 4.8, 2.8 and 2, typical for Gd3+ ions uniformly distributed in the glass and glass ceramic samples. For higher contents of gadolinium ions (x >= 3 mol%) the EPR spectra are dominated by a single broad line centered at g similar to 2, which can be due to the magnetic clusters containing Gd3+ ions. The magnetic susceptibility data show that the gadolinium ions are involved in superexchange interactions in all the investigated glass ceramics, being antiferromagnetically coupled.