Theoretical design of novel half-metallic alloys XMg3O4(X = Li, Na, K, Rb)

First-principles calculations, based on the density functional theory (DFT), have been used to predict the structural, elastic, electronic and magnetic properties of XMg3O4 (X = Li, Na, K and Rb) compounds. They have been performed by employing the full-potential linearized augmented plane wave method (FP-LAPW), as implemented in Wien2k code. It was found that all compounds were ferromagnetic by energy minimization procedure. The computations of elastic constants show that our compounds are mechanically stable. The electronic properties, through the density of states and band structures, indicate that these compounds exhibit half-metallic nature, and the spin up band gaps (HMgaps) were found to be5.32 (0.18) eV, 4.49 (0.28) eV, 3.01 (0.38) eV and 1.53 (0.17) eV for LiMg3O4, NaMg3O4, KMg3O4 and RbMg3O4, respectively. In addition, for all compounds, the calculated integer magnetic moment value of 1.0 µB fulfills the necessary condition of the half-metallicity. The calculated Curie temperatures $${T}_{c}$$ are 537, 365, 260 and 113 K for LiMg3O4, NaMg3O4, KMg3O4 and RbMg3O4, respectively.