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We theoretically investigate the electronic and magnetic properties of the recently reported cubic and orthorhombically (Ortho.) distorted phases of PbMoO3, a 4d transition-metal perovskite oxide with almost half-filled t2g states. Our spin-polarized bare generalized gradient approximation results exhibit that the cubic phase is of low energy structure than the Ortho. one. However, on-site Coulomb repulsion in the range of 3.3 eV≤Ueff≤4.5 eV inclusion on Mo 4d orbitals reveals that at each value of Ueff, the Ortho. phase is more stable than the cubic one and with the increase in Ueff, both phases show more stability. We find a non-magnetic n-type conductivity with a high charge carrier density of ~1022cm-3 in both phases. Interestingly, a non-magnetic to magnetic phase transition occurs at Ueff=3.8 eV and 3.5 eV for the cubic and Ortho. phases, respectively. Moreover, a half-metallic ferromagnetic state is obtained at Ueff=4.1 eV and 4.3 eV for the cubic and Ortho. phases, respectively. Calculations also indicate a strong orbital hybridization between Pb 6p and Mo 4d, with a significant contribution of O 2p states. All findings are confirmed by the Yukawa screened Perdew-Burke-Ernzerhof 0 (YS-PBE0) hybrid functional. This work provokes further experimental investigations of magnetic properties of PbMoO3. [ABSTRACT FROM AUTHOR]

Using density functional theory calculations, we found that recently high-pressure synthesized double perovskite oxide Lu 2 NiIrO 6 exhibits ferrimagnetic (FiM) Mott-insulating state having an energy band gap of 0.20 eV which confirms the experimental observations (Feng et al. in Inorg Chem 58:397–404, 2019). Strong antiferromagnetic superexchange interactions between high-energy half-filled Ni + 2 - e g 2 ↑ and low-energy partially filled Ir + 4 t 2 g 3 ↑ t 2 g 2 ↓ orbitals, results in a FiM spin ordering. Besides, the effect of 3d transition metal (TM = Cr, Mn, and Fe) doping with 50% concentration at Ni sites on its electronic and magnetic properties is explored. It is established that smaller size cation-doping at the B site enhances the structural distortion, which further gives strength to the FiM ordering temperature. Interestingly, our results revealed that all TM-doped structures exhibit an electronic transition from Mott-insulating to a half-metallic state with effective integral spin moments. The admixture of Ir 5d orbitals in the spin-majority channel are mainly responsible for conductivity, while the spin minority channel remains an insulator. Surprisingly, a substantial reduction and enhancement of spin moment are found on non-equivalent Ir and oxygen ions, respectively. This leads the Ir ion in a mixed-valence state of + 4 and + 5 in all doped systems having configurations of 5 d 5 ( t 2 g 3 ↑ t 2 g 2 ↓ ) and 5 d 4 ( t 2 g 2 ↑ t 2 g 2 ↓ ), respectively. Hence, the present work proposes that doping engineering with suitable impurity elements could be an effective way to tailor the physical properties of the materials for their technological potential utilization in advanced spin devices. [ABSTRACT FROM AUTHOR]

Interfacial perpendicular magnetic anisotropy in the Fe/MgO heterostructure has attracted increasing attention because of its potential usage in building out-of-plane magnetized magnetic tunnel junctions for spin-transfer-torque magnetic random-access memory devices. A large interfacial anisotropy constant (Ki) is required to achieve a high thermal stability that is critical for large-capacity magnetic tunnel junctions. Here, we show that inserting one layer of appropriate heavy elements (X) at the interface of Fe/MgO can significantly enhance Ki using first-principles electronic structure calculations. A total number of 33 X metal elements including 3d, 4d, and 5d transition metals and 4p, 5p, and 6p main group elements were considered. By analyzing the interfacial magnetic anisotropy and interfacial bonding strength of Fe/X/MgO, we are able to identify three promising heavy transition-metal elements including W, Re, and Pt for enhancing perpendicular magnetic anisotropy in Fe/MgO, with an improved Ki of 2.43, 2.37, and 9.74 mJ/m2, respectively. This work indicates that interfacial engineering is one effective way to modify the interfacial magnetic anisotropic property. [ABSTRACT FROM AUTHOR]