The electronic structure and magnetic properties of the full-Heusler alloys Co2TiX (X element from groups III, IV and V) were studied by first principle calculations. Previous calculations found Co2TiAl and Co2TiSn not to be half metallic. In this paper, however, it will be shown that the alloys with X=Al,Si,Ge,Sn are half metallic and ferromagnetic. The effect of atomic disorder in the Ti–Al sublattices reduces the half metallicity of the Co2TiAl Heusler alloy.

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Using micromagnetic simulations, the authors investigate the effects of the shape anisotropy of nanowires on the threshold current density (JC) in the adiabatic limit. It is observed that the type of domain wall significantly affects the dependence of JC on the shape anisotropy. For a transverse wall, JC is proportional to the shape anisotropy, but slightly deviates from the theoretical prediction [G. Tatara and H. Kohno, Phys. Rev. Lett. 92, 086601 (2004)] possibly due to antivortex formation. For a vortex wall, JC is almost independent of the shape anisotropy, as experimentally observed [A. Yamaguchi et al., Jpn. J. Appl. Phys. Part 1 45, 3850 (2006)]. Interestingly, JC and the velocity of the vortex wall at finite temperatures are in good agreement with the experimental values even when the nonadiabatic spin torque is not considered.

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Recent experiments have demonstrated high tunneling magnetoresistance (TMR) ratios in magnetic tunnel junctions (MTJs) with the MgO barrier. The CoFeB∕MgO∕CoFeB junctions showed better properties than the CoFe∕MgO∕CoFe junctions because the MgO layer had a good crystalline structure with (001) texture and smooth and sharp interface between CoFeB∕MgO. In this work, the compositional changes in the MgO barrier and at the interface of CoFeB∕MgO∕CoFeB after the CoFeB crystallization were studied in annealed MTJs. X-ray photoelectron spectroscopy depth profiles were utilized for the as-deposited and 340°C annealed specimens. Transmission electron microscope analyses showed that the MgO barrier had (100) texture on CoFeB in the junctions and CoFeB was crystallized in the annealed junctions. B in the bottom CoFeB layer diffused into the MgO barrier and B–oxide was formed at the interface of CoFeB∕MgO∕CoFeB after the CoFeB crystallization. The B behavior will be discussed.