Used in the production of special alloys for aircraft engines due to its high thermal stability and resistance to oxidation. Employed in fluoride glass for fiber optics, enhancing infrared transmission. Serves as a dopant in solid-state lasers and optical amplifiers. Applied in the manufacturing of high-strength permanent magnets when alloyed with other rare-earth elements. Utilized in nuclear reactors as a control rod material because of its neutron absorption properties. Also found in certain types of welding electrodes to improve arc stability and reduce spatter.