Used as a host material in phosphors for cathode ray tubes and fluorescent lamps due to its ability to emit red light when doped with europium. Commonly employed in solid-state lasers, especially in yttrium aluminum garnet (YAG) crystals, enhancing performance in medical, industrial, and military laser systems. Serves as a stabilizer for zirconia in high-temperature ceramics, improving thermal shock resistance in aerospace and energy applications. Applied in coatings for optical lenses to increase refractive index and durability. Utilized in the production of superconductors and as a component in sensors and fuel cell materials owing to its ionic conductivity at elevated temperatures.