Spectroscopic behavior of Nd 3+ in a new microcrystalline ZnY 4W 3O 16 tungstate

Abstract

In the framework of systematic investigations of the optical properties of a new tungstate ZnY 4W 3O 16 in which Y 3+ cations allow for rare-earth ions doping, the compounds doped with neodymium Nd 3+ ion were synthesized, analyzed and considered as a possible laser material. The crystalline stoichiometric sample of the chemical formula ZnNd 4W 3O 16 and their yttrium diluted analogues 0.5, 1, 5 and 10 mol% Nd 3+-doped ZnY 4W 3O 16 were obtained by a solid-state reaction. X-ray powder diffraction analysis as well as the IR spectra were used to the structural characterization of the compounds. Electron microscopy has been used to analyze the grain size, the presence of aggregates, and the type of boundary between the microcrystals. In order to study spectroscopic properties, the high resolution absorption and emission spectra at room and low temperature were measured in visible and IR regions. The radiative transition probabilities in those tungstates were calculated and analyzed. Based on the 4 K absorption spectra in the range of 4I 9/2 → 2P 1/2 transition the number of metal sites occupied by the dopants was determined. The strong fluorescent emission involving the 4F 3/2 → 4I 9/2, 4I 11/2, 4I 13/2 transitions at 298 and 77 K were observed under pulsed laser and xenon lamp excitation. The dynamics of the Nd 3+ excited states were characterized by decay times measurements and compared to earlier reported data for neodymium tungstates.