Influence of yttrium on EPR characteristics of chromium ions in nanoscale particles of zirconium dioxide

The EPR and proton magnetic resonance methods were applied to study zirconium hydroxide samples which transformed to nanoscale ZrO2 powders upon annealing. The samples were obtained from solutions with mixture compositions (ZrO2 + 0.5 mol % Cr2O3) and (ZrO2 + 3 mol % Y2O3 + 0.5 mol % Cr2O3). The influence of yttrium on the recharging of the chromium ion upon annealing of samples was studied in the temperature range 100–950°C. A significant influence of yttrium on internal stresses caused by heating and cooling in the lattice of nanoscale ZrO2 particles was detected using the EPR method. It was shown that the typical features of the influence of yttrium on total (over the entire crystallite) and local (near chromium ions) lattice distortions depend on the sample heating temperature and are different for various annealing temperatures.