Room-Temperature Ferromagnetic Semiconductors in Alloyed Spinels ACr_1.5W_0.5X₄ (A = Cd, Zn, Hg; X = S, Se, Te)

Ferromagnetic (FM) semiconductors with intrinsic spontaneous net magnetizations and semiconductivity show great potential in future spintronic applications such as low-energy-cost random access memories. However, room-temperature FM semiconductors have not yet been discovered, which hinders their practical applications. In this work, using first-principles calculations, we show that Curie temperature (T-C) of the conventional FM semiconducting spinels ACr(2)X(4) (A = Cd, Zn, Hg; X = S, Se, Te) can be significantly increased via partially replacing the Cr by W ions. The alloyed structures of ACr(1.5)W(0.5)X(4) are predicted to be intrinsic room-temperature FM semiconductors with diverse electronic bandgaps. Among them, CdCr1.5W0.5Se4 shows T-C of similar to 310 K, which is more than doubled that (similar to 150 K) of the pristine CdCr2Se4. These findings provide a new route to realize room-temperature FM semiconductors, which will be of great interest for the development of spintronics.