Influence of gadolinium tantalum niobates doped with Eu3+ ions structural properties on luminescence spectrum features

For the first time, a series of ceramic solid solutions of gadolinium tantalum niobates activated by europium was synthesized. A detailed interpretation of the obtained ceramics luminescence spectra was performed in the range of 580–630 nm for photoluminescence and 390–720 nm for cathodoluminescence. The transitions from 5D0, 5D1, 5D2 and 5D3 radiative levels of Eu3+ were observed in cathodoluminescence spectra of the samples. The main structural phase of the samples corresponded to the monoclinic structure with I2/a space group. The dependence of the europium luminescence bands Stark splitting on the Nb/Ta ratio in the material was studied for various radiative transitions. It was demonstrated that the distance between Eu3+ luminescence bands splitting increased in the solid solution series from GdNbO4 to GdTaO4. It can be due to an increase in the local field action on the Eu3+ ions. •Ceramic of Gd0.94Eu0.06NbxTa1–xO4 have been synthesized for the first time.•A detailed interpretation of Eu3+ luminescence spectra in GdNbTaO4 has been performed.•The dependence of the Eu3+ levels Stark splitting on the Nb/Ta ratio was studied.•With an increasing of Ta content in the material, the Stark splitting increases.