Yang Haozhe, Li Yi, Zeng Min, Cao Wei, Bailey William E, Yu Ronghai
School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
Materials Science Engineering, Department of Applied Physics Applied Mathematics, Columbia University, New York 10027, USA.
Sci Rep. 2016 Feb 11;6:20427. doi: 10.1038/srep20427.
FeNi binary nanowires with gradient composition are fabricated by the electrodeposition method. The energy dispersive spec-trometer line-sweep results show that the composition changes gradually along the wire axis. The gradient FeNi nanowires exhibit polycrystalline and crystal twinning at different areas along the nanowire axis, with a textured face-centered cubic structure. The static and dynamic magnetization properties are characterized by a hysteresis loop and ferromagnetic reso-nance with pumping frequencies from 12- 40 GHz. The linear dispersion of the pumping frequency vs: the resonance field has been observed with the applied bias field higher than the saturation field, corresponding to the hysteresis loop. The field-sweep linewidths decrease with increasing pumping frequency, and the frequency-sweep linewidths stay nearly constant at the unsaturated region. The linewidth is a Gilbert type at the saturated state, with damping of 0.035 ± 0.003. Compared with the damping of the homogeneous composition FeNi nanowire (a = 0.044 ± 0.005), the gradient FeNi nanowire may have less eddy current damping, which could make it an alternative candidate for spintronics and microstrip antennas.
采用电沉积法制备了具有梯度成分的FeNi二元纳米线。能量色散谱仪线扫描结果表明，成分沿线轴逐渐变化。梯度FeNi纳米线在沿纳米线轴的不同区域呈现多晶和晶体孪晶，具有织构面心立方结构。通过磁滞回线和12 - 40 GHz泵浦频率的铁磁共振对静态和动态磁化特性进行了表征。在高于饱和场的外加偏置场下，观察到泵浦频率与共振场的线性色散，这与磁滞回线相对应。场扫描线宽随泵浦频率增加而减小，在不饱和区域频率扫描线宽几乎保持不变。在饱和状态下线宽为吉尔伯特型，阻尼为0.035±0.003。与均匀成分FeNi纳米线的阻尼（a = 0.044±0.005）相比，梯度FeNi纳米线可能具有较小的涡电流阻尼，这使其成为自旋电子学和微带天线的替代候选材料。
