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We report first-principles investigation on structural, electronic and magnetic properties of 3d transition metal element-doped rock-salt calcium selenide Ca 1 − x TMxSe (TM = V, Cr and Mn) at concentrations x = 0.0625, 0.125 and 0.25. We performed the calculations in the framework of the density functional theory (DFT) using the full-potential linearized augmented plane waves plus local orbitals (FP-LAPW+lo) method within the Wu–Cohen generalized gradient approximation (WC-GGA) for the structural optimization and the Tran–Blaha modified Becke–Johnson (TBmBJ) potential for the electronic and the magnetic properties. The computed spin-polarized band structures and densities of states show that Ca 1 − x CrxSe compounds at all studied concentrations are half-metallic ferromagnets with a complete spin polarization of 100% at Fermi-level while the Ca 1 − x VxSe and Ca 1 − x MnxSe are ferromagnetic semiconductors. The total magnetic moments for Ca 1 − x VxSe, Ca 1 − x CrxSe, and Ca 1 − x MnxSe show the integer values of 3 μ B , 4 μ B , and 5 μ B , respectively, with a major contribution of transition metal elements (TM) in the total magnetization. Also, we reported the calculated exchange constants N 0 α and N 0 β and the band edge spin splitting of the valence (Δ E v ) and conduction (Δ E c ) bands. The ferromagnetism of these compounds is due to the super-exchange and the double-exchange mechanisms in addition to the strong p–d exchange interaction. Therefore, the predicted results indicate that the diluted Ca 1 − x TMxSe (TM = V, Cr, Mn) compounds are suitable candidates for a possible application in the field of spintronic technology. [ABSTRACT FROM AUTHOR]

Herein, we propose and provide evidence for the experimentally and theoretically promising route of exploring spintronics materials with high performance via a synthetic hybrid of half-metallic ferromagnet and diluted magnetic semiconductor. Crystalline and well-ordered [Co2FeGe/Ge(Mn)]n superlattice, which is free of secondary phase separation, were prepared by the hybridization of end members, Co2FeGe and Ge(Mn), using the molecular beam epitaxy technique. Besides comparable magnetic properties with respect to the Co2FeGe films, the superlattice sample exhibits superior properties in electric conductivity and spin polarization, thus enhancing in favor of the spin injection efficiency. These results demonstrate the high feasibility of spintronics materials with low saturation magnetization, small coercivity, high Curie temperature, and high spin injection efficiency through the proposed route in this work. [ABSTRACT FROM AUTHOR]

The presence of spin polarization in Mn-doped ZnO thin film is very important for spintronic applications. Spin polarization was detected using simple method. This method depends on measuring the optical transmittance using circular polarized light in visible and near infra-red region. It was found that, there is a difference in the optical energy gap of the film for circular left and circular polarized light. For temperatures > 310 K the difference in energy gap is vanished. This result is confirmed by measuring the magnetic hysteresis of the film. This work introduces a promising method for measuring the ferromagnetism in diluted magnetic semiconductors. [ABSTRACT FROM AUTHOR]

Spin polarized van der Waals (vdW) heterostructures have attracted considerable interest owing to the spin splitting manipulation. In this paper, first-principles calculations are employed to explore the two-dimensional arsenene/CrI 3 vdW heterostructure as a promising spin polarized material, as well as the spin polarization under strain and electronic field are investigated. The most stable stacking configuration and ferromagnetic (FM) property of the arsenene/CrI 3 vdW heterostructure have been confirmed. The detailed calculations show that the Curie temperature (T c) of the FM coupling CrI 3 layer in the heterostructure can be enhanced up to 61 K, which is attributed to both superexchange interaction and proximity exchange effect. The electronic structures suggest that this heterostructure possess an intrinsic type-II band alignment and diluted magnetic semiconductor property. Interestingly, we found a transition from diluted magnetic semiconductor to half-metal and gradually to metal induced by the biaxial strains, and the extra electronic field can modulate the "maxican hat" of the valance band maximum (VBM) of arsenene. Our work provides not only application prospects of the arsenene/CrI 3 vdW heterostructure nanodevices but also theoretical effective support for the research and development of the spin electronics and flexible electronics. • The arsenene/CrI 3 heterostructure possess an intrinsic type-II band alignment and diluted magnetic semiconductor property. • Biaxial strains can make arsenene/CrI 3 heterostructure transform from diluted magnetic semiconductor to half-metal and gradually to metal. • Electronic field can change the contribution of As and I atoms in VBM, enlarge the band gap. [ABSTRACT FROM AUTHOR]

In search of d 0 magnetism, the magnetic behavior of SnO 2 with cation substitution from group1A (Li, Na, K) and group 2A (Be, Mg, Ca) elements has been systematically studied using Density Functional Theory (DFT). While an impurity from group 1A elements switches on ferromagnetism at a lower concentration itself, sufficient hole density is required for a group 2A impurity to create a spontaneous spin polarized ground state, a finding that has not been reported in earlier investigations. Our DFT results predict for the first time that impurities from group 2A (Mg, Ca) in SnO 2 can promote room temperature ferromagnetism. Further, the emergence of ferromagnetism due to doping from group 1A elements, which injects three holes per defect, has been mapped successfully onto a modified Hubbard model from the literature. Doping of a single Na atom in the supercell (concentration 6.25 at%) makes the system ferromagnetic, with a magnetic moment close to 3.0 μ B per defect, and a Curie temperature of 815 K, obtained in the mean field approximation. This agrees closely with a model prediction of 750 K. Finally, the triggering of ferromagnetism by an impurity atom from group 2A, which adds two holes per defect in the system, implies that the prescription of three holes per defect given in the literature is not a necessary criterion for hole induced ferromagnetism. Rather, the analysis of the density of states and ferromagnetic coupling indicate that the system needs a critical hole concentration to activate ferromagnetism, by pushing the Fermi level inside the valence band in order to satisfy the Stoner criterion. [ABSTRACT FROM AUTHOR]

In the present work, theoretical investigations of structural, electronic, magnetic, and thermoelectric properties of Cd 0.875 TM 0.125 O (TM = Mn, Fe, Co, Ni) half-metallic ferromagnets are done using WIEN2K code. The computed results when compared with the reported theoretical works reveal consistency. The band structures for spin up (↑), and spin down (↓) channels reveal the half metallic (Mn, Co, Fe), and frustrated (Ni) magnetism. The nature of magnetism has been analyzed in terms of hybridization among 3d states of TMs, individual Cd (5s, 4d) states, and O (2p) states. The control and function of the electron spin are revealed by calculating exchange energies (Δ x (d), Δ x (pd)), crystal field energy (ΔE cryst) and exchange constant (N o α, N o β), those play a very crucial role in understanding the magnetic nature. Moreover, double exchange and RKKY models are discussed to justify the observed half-metallic, and metallic behaviors, which are responsible for the magnetic moments to stabilize a magnetic polarization. The influence of electron spin is explained using the computed electrical and thermal conductivities, while thermoelectric power is elaborated by computing Seebeck coefficient and power factor. • Above room temperature ferromagnetism, and spintronic applications •Quantum spin of electrons dominant the charge with multifuctional properties •Exchange mechanism certifies the ferromagnetism by electron spin instead of magnetic ion clustering •Half metallic ferromagnetism and 100% spin polarization •Large value of electrical conductivity and ultralow low values of thermal conductivity. [ABSTRACT FROM AUTHOR]