Influence of cerium on the spectral and structural characteristics of LuBO$_{3}$(Ce, Tb)

Studies of the structure, IR absorption spectra, luminescence spectra, and excitation of luminescence of Ce$^{3+}$ and Tb$^{3+}$ ions in crystals of solid solutions of Lu$_{1-x-y}$Ce$_{x}$Tb$_{y}$BO$_{3}$ at 0 $\le x\le$ 0.01 and 0.07 $\le y\le$ 0.16. have been performed. It has been shown that the solid solution Lu$_{1-y}$Tb$_{y}$BO$_{3}$ synthesized at $T$ = 970$^\circ$C has the structure of calcite at 0 $\le y\le$ 0.07, at $y>$ 0.16–the structure of vaterite, and in the range 0.07 $<y<$ 0.16 is two-phase. It has been found that additional doping of 0.5 – 1 at% Ce$^{3+}$ of two-phase Lu$_{1-y}$Tb$_{y}$BO$_{3}$ samples, in which the proportion of the vaterite phase does not exceed $\sim$20%, leads to a significant reduction of the vaterite phase. It has been shown that Ce$^{3+}$ ions can be used as structurally sensitive and optically active marks in the analysis of the structural state of rare earth element orthoborates.