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Microwave spin pumping at ferromagnetic resonance from ferromagnetic films into nonmagnetic films is an efficient method to realize spin injection. The spin injection efficiency is proportional to the spin mixing conductance and can be detected by measuring voltages converted from spin current via the inverse spin Hall effect. In this work, we modified the properties of the ferromagnetic layer by thermal annealing. The results show that the crystal quality of the ferromagnetic films, as well as the magnetic properties has been greatly modified while the spin mixing conductance is insensitive to it. The work represent an incentive to work on engineering the spin Hall angle of the nonmagnetic layer to improve the spin Hall effect or the inverse spin Hall effect. [ABSTRACT FROM AUTHOR]

Abstract: Barium ferrite films were prepared by spin-coating of gels on sapphire (00 l) faces. Ethylenediaminetetraacetic acid was used to bind the metal ions. Thin films prepared by this method show faceted hexagonal grains with c-axis normal to the film plane and [110]sapphire ||[100]film. Needle-like grains, which have c-axis in the film plane, are minimized. Epitaxial growth of the film can be observed by the high resolution images. Reduction of the a and c-axis of the film compared with those of the bulk materials is confirmed both in real space and reciprocal space. Magnetic hysteresis loops were recorded in-plane and out-of-plane. The film shows uniaxial anisotropy as exemplified by branched domains with coercivity field of 87.6kA/m along the in-plane direction and of 302.5kA/m along the out-of-plane direction. [Copyright &y& Elsevier]

Abstract: Hexagonal barium ferrite (BaM) thin films have been prepared by sol–gel technique involving spin coating and annealing in air. Different ratios of Ba to Fe, different annealing temperatures and different annealing time are explored. X-ray diffraction shows that the films have been epitaxially grown on the sapphire (001) plane with [100] direction of BaM parallel to [110] of Al2O3, and the c-axes of them being parallel, while magnetic measurements show magnetically anisotropic loops with in-plane and out-of-plane intrinsic coercivity of 87.5kA/m and 230.8kA/m, respectively. [Copyright &y& Elsevier]

The effects of the planar shape anisotropy and biasing field on the magnetization reversal process (MRP) of the diamond-shaped NiFe nano films have been investigated by micromagnetic simulations. Results show that when the length to width ratio (LWR) of the diamond-shaped film is small, the MRP of the diamond-shaped films are sensitive to LWR. But when LWR is larger than 2, a stable domain switching mode is observed which nucleates from the center of the diamond and then expands to the edges. At a fixed LWR, the magnitude of the switching fields decrease with the increase of the biasing field, but the domain switching mode is not affected by the biasing field. Further analysis shows that demagnetization energy dominates over the MRP of the diamond-shaped films. The above LWR dependence of MRP can be well explained by a variation of the shape anisotropic factor with LWR. [ABSTRACT FROM AUTHOR]

Abstract: It is important to control magnetic anisotropy of ferromagnetic materials. In this work, magnetic anisotropy of amorphous FeCoSiB films is controlled by stress annealing. FeCoSiB films are deposited on glass substrate and annealed with stress in vacuum. When the annealed films are released from clamp, permanent tensile or compressive strain can be introduced in the films. Influences of both tensile and compressive strain on the magnetic properties of FeCoSiB films have been studied. The results show that FeCoSiB films by stress annealing exhibit strong magnetic anisotropy while the samples by normal annealing exhibit magnetic isotropy. Easy axis along the stress is induced in the films with tensile stress, while easy axis perpendicular to the stress is induced in the samples with compressive stress. It has also been found that the magnetic anisotropy increases with the increase of the strain. The effects of strain on the magnetic properties of FeCoSiB films have been interpreted by stress induced anisotropy via magnetoelastic coupling. [Copyright &y& Elsevier]