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In order to achieve a controllable spin-polarized source, we have applied a transverse electric field to a spin filter based on a novel magnetic nanostructure with zero average magnetic field. We have analytically calculated the transmission coefficient, conductance and spin polarization for electrons to transit the device in the presence of a transverse electric field. The results demonstrate that the transmission, the conductance and the spin polarization vary sensitively with the electric field. It is shown that the performance of the spin filter can be manipulated expediently by adjusting the transverse electric field. Thus, the spin filter can be utilized as an electrically controllable spin-polarized source for spintronics applications. [ABSTRACT FROM AUTHOR]

A highly supersaturated nanocrystalline Cr-25 wt% Zr alloy has been prepared by mechanical alloying of elemental crystalline powders. High-purity powders of Cr and Zr were milled for up to 20 h. The development of the microstructure was investigated by X-ray diffraction (XRD) and scanning electron microscopy. XRD patterns confirmed complete alloying of the Zr and Cr. The contribution of grain boundaries, the chemical potential of a solute atom induced by dislocations, and the elastic strain energy arising from the different sizes of Cr and Zr atoms have been calculated. The alloy formation is discussed with respect to the thermodynamic conditions of the material. The role of internal strains and stored enthalpies by dislocations on solute atoms is the major mechanical driving force for alloying and this is critically assessed in this article. [ABSTRACT FROM AUTHOR]

The powder metallurgy technology of mechanical alloying followed by hot-pressing consolidation has been used to obtain NbCr2-Ni Laves phases. High-purity Nb, Cr, and Ni crystalline powders were milled for periods up to 35 h. These powders were vacuum sintered at 1250°C for 0.5 h under 45 MPa. The phase transformations of NbCr2-Ni Laves phases have been investigated by X-ray diffraction. The grain size decreases and the microstrain increases with increased Ni content. Different phase transformations were observed from NbCr2-Ni intermetallics. It is found that the electron concentration and phase stability correlation is obeyed in the Nb-Cr-Ni systems. However, the electron concentration corresponding to the C15/C14 phase transition is found to move to a higher value (i.e. 6.103) than the predicted one (i.e. 5.88) in the literature. [ABSTRACT FROM AUTHOR]