Theoretical prediction of half-metallic materials in double perovskites Sr2Cr(Co)B′O6 (B′ = Y, La, Zr, and Hf) and Sr2V(Fe)B′O6 (B′ = Zr and Hf)

• Double perovskite.
• Structure optimization.
• Stable magnetic phase.
• 4 HM materials.

In this work, we have investigated stable half-metallic materials of the double perovskites Sr2BB′O6: Sr2Cr(Co)B′O6 (B′ = Y, La, Zr and Hf) and Sr2V(Fe)B′O6 (B′ = Zr and Hf). Based on the density functional theory, the calculations are conducted with full structural optimization. Generalized gradient approximation (GGA) and additional correlation effect (GGA+U) are used. In the GGA+U scheme, the energy gaps of Sr2CoZrO6 are opened in both spin-channels and become ferromagnetic insulators (FM-Is); Sr2CoZrO6, Sr2CoHfO6, Sr2FeZrO6, and Sr2FeHfO6 transfer from low-spin state to high-spin state. The half metallicity are attributed by the double-exchange interaction mechanism via the B(t2g)–O(2p)–B’(t2g) π-bounding.