Spectroscopic and magnetic behavior of Gd and Nd ions in lead–germanate glasses

Abstract

Samples of the xGd2O3(1−x)[GeO·PbO] and xNd2O3(1−x)[GeO·PbO] vitreous systems with 0≤x≤0.15 were prepared and investigated by X-ray diffraction, FTIR spectroscopy and magnetic susceptibility measurements (in addition, the samples containing gadolinium ions were investigated by electron paramagnetic resonance (EPR) spectroscopy). FTIR spectroscopy investigation shows that the studied samples consist of both GeO4 and GeO6 structural units, the GeO4 being predominant. The increase of the gadolinium or neodymium ion content of the samples determines the GeO4→GeO6 conversion process. FTIR data suggest that the rare earth ions present in the vitreous matrix play a network modifier role. Magnetic susceptibility data show that the magnetic behavior of the studied samples is due to the presence of the Gd3+ and Nd3+ ions. These ions appear as isolated species for low rare earth oxide contents, x≤0.03–0.05, while for higher contents appear as magnetically coupled species, too.EPR spectroscopy data obtained for the xGd2O3(1−x)[GeO2·PbO] samples show that, in addition to the network modifier role of the rare earth ions suggested by the FTIR data, the Gd3+ ions play also the network former role.