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Several rocksalt Sr 4 X 3 N (X=O,S,Se,and Te) are predicted to be potential half-metallic ferromagnets free of transition-metal and rare-earth elements by performing the first-principles calculations.Then their magnetic properties,such as the half metallicity and the crystal-cell magnetic moments are investigated.The Sr 4 X 3 N possibly have higher Curie temperatures and have more stable half metallicity than the Sr 4 X 3 C.Their crystal-cell magnetic moments are all 1.00 μ B.The crystal-cell magnetic momen...","Several rocksalt Sr4X3N (X =O,S,Se,and Te) are predicted to be potential half-metallic ferromagnets free of transition-metal and rare-earth elements by performing the first-principles calculations.Then their magnetic properties,such as the half metallicity and the crystal-cell magnetic moments are investigated.The Sr4X3N possibly have higher Curie temperatures and have more stable half metallicity than the Sr4X3C.Their crystal-cell magnetic moments are all 1.00 μB.The crystal-cell magnetic moments and the half metallicity arise mainly from the N ions.The main mechanism is the strong covalent interaction leading to the sp2 hybridized orbitals in the Sr4X3N.Then two Sr-5s and three N-2p electrons enter into three sp2 hybridized orbitais.Among these five electrons,four electrons are paired and one is unpaired,so there are three spin-up electrons and two spin-down electrons in these sp2 hybridized orbitals.