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    Transient spin injection efficiencies at ferromagnet/metal interfaces
    (Weinheim : Wiley-VCH, 2022-10-19) Elliott, Peter; Eschenlohr, Andrea; Chen, Jinghao; Shallcross, Sam; Bovensiepen, Uwe; Dewhurst, John Kay; Sharma, Sangeeta
    Spin injection across interfaces driven by ultrashort optical pulses on femtosecond timescales constitutes a new way to design spintronics applications. Targeted utilization of this phenomenon requires knowledge of the efficiency of non-equilibrium spin injection. From a quantitative comparison of ab initio time-dependent density functional theory and interface-sensitive, time-resolved non-linear optical experiment, the spin injection efficiency (SIE) at the Co/Cu(001) interface is determined, and its microscopic origin, i.e., the influence of spin-orbit coupling and the interface electronic structure, is discussed. Moreover, we theoretically predict that the SIE at ferromagnetic–metal interfaces can be optimized through laser pulse and materials parameters, namely the fluence, pulse duration, and substrate material.
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    Electronic, magnetic, optical and thermoelectric properties of Ca2Cr1−xNixOsO6 double perovskites
    (London : RSC Publishing, 2020) Bhandari, Shalika R.; Yadav, D.K.; Belbase, B.P.; Zeeshan, M.; Sadhukhan, B.; Rai, D.P.; Thapa, R.K.; Kaphle, G.C.; Ghimire, Madhav Prasad
    With the help of density functional theory calculations, we explored the recently synthesized double perovskite material Ca2CrOsO6 and found it to be a ferrimagnetic insulator with a band gap of ∼0.6 eV. Its effective magnetic moment is found to be ∼0.23 μB per unit cell. The proposed behavior arises from the cooperative effect of spin–orbit coupling and Coulomb correlation of Cr-3d and Os-5d electrons along with the crystal field. Within the ferrimagnetic configuration, doping with 50% Ni in the Cr-sites resulted in a half-metallic state with a total moment of nearly zero, a characteristic of spintronic materials. Meanwhile, the optical study reveals that both ε1xx and ε1zz decrease first and then increase rapidly with increasing photon energy up to 1.055 eV. We also found optical anisotropy up to ∼14 eV, where the material becomes almost optically isotropic. This material has a plateau like region in the σxx and σzz parts of the optical conductivity due to a strong 3d–5d interband transition between Cr and Os. In addition, we performed thermoelectric calculations whose results predict that the material might not be good as a thermoelectric device due to its small power factor.