Structure, phase composition, and spectral luminescence properties of partially stabilized zirconium dioxide crystals doped with Yb$^{3+}$ ions

Investigation of partially stabilized zirconium dioxide crystals via transmission electron microscopy has revealed a developed twin structure therein. The following compositions of the above crystals have been selected for this study: 97.2 mol. % ZrO$_{2}$ – 1.0 mol. % Y$_{2}$O$_{3}$ – 1.8 mol. % Yb$_{2}$O$_{3}$, 97.2 mol. % ZrO$_{2}$ – 2.0 mol. % Y$_{2}$O$_{3}$ – 0.8 mol. % Yb$_{2}$O$_{3}$, 97.2 mol. % ZrO$_{2}$ – 2.5 mol. % Y$_{2}$O$_{3}$ – 0.3 mol. % Yb$_{2}$O$_{3}$ и 96.3 mol. % ZrO$_{2}$ – 3.4 mol. % Y$_{2}$O$_{3}$ – 0.3 mol. % Yb$_{2}$O$_{3}$. X-ray diffraction analysis of these crystals indicate the presence of transformable $(t)$ and nontransformable $(t')$ tetragonal phases. Optical spectroscopy measurements of ZrO$_{2}$–Y$_{2}$O$_{3}$–Yb$_{2}$O$_{3}$ crystals with tetragonal and cubic structures have highlighted in Yb$^{3+}$-doped zirconium dioxide samples the formation of the optical centers of the Yb$^{3+}$ ions is observed, whose crystal surrounding is similar to those in cubic zirconium dioxide crystals.