Structural and cathodoluminescent properties of ceramics based on Gd1-xEuxNbyTa1-yO4 solid solutions

Abstract

Series of ceramics based on Gd1-xEuxNbyTa1-yO4 (x = 0.01; 0.02; 0.06; 0.1; 0.2; 0.4) solid solutions with different Nb\\Ta ratio were obtained for the first time. A detailed study of the structural and cathodoluminescent (CL) properties of the obtained materials was carried out. All samples had a monoclinic structure with I2/a space group (M-polytype). The content of phase impurities in some samples did not exceed 3-10 rel.%. CL bands attributed to transitions from 5D0, 5D1, 5D2, 5D3 levels to the 7Fj (j = 0-5) Eu3+ levels were observed in the CL spectra in the range of 350-750 nm. Concentration quenching of Eu3+ ions CL intensity occurred at concentrations from 0.1 to 0.2 form. un. of Eu3+. The Eu3+ CL intensity did not evidently depend on the Nb/Ta ratio for most of the samples. 5D0-7F2 Eu3+ transition decay kinetics was approximated with the sum of two exponentials. The presence of shorter decay time was associated with Eu3+ luminescence centers with an increased probability of nonradiative recombination located near extended defects and ceramic grain boundaries.