SmB6

Samarium hexaboride (SmB₆) is a rare-earth ceramic compound belonging to the hexaboride family, prized for its exceptional thermionic emission properties and metallic-like electrical conductivity despite its ceramic structure. It is primarily used in high-temperature vacuum applications, particularly as a cathode material in electron guns, mass spectrometry, and advanced thermal imaging systems, where its ability to efficiently emit electrons at elevated temperatures outperforms conventional tungsten alternatives. Engineers select SmB₆ for extreme-environment applications where long service life, low work function, and thermal stability are critical; however, its cost and material brittleness limit adoption to specialized military, aerospace, and research-grade instrumentation.