一维Co单晶纳米线的x射线研究

X-ray diffraction investigation of single-crystal Co nanowires

对电化学沉积法在多孔氧化铝中制备的一维单晶Co纳米线阵列的结构和形态利用各种x射线衍射测量方法进行了细致的表征 .确定了阵列中的纳米线在线长方向均为一致的晶体学取向 ,并以很高的平行度排列 .并且发现生长条件可能在一维纳米线中引起不同程度的螺旋晶格曲扭 .根据实验观察结果提出了一个具有手性的螺旋曲扭模型 .利用超导量子干涉磁强计测量了样品在 30 0K下的磁特性 ,分析发现螺旋扭曲可以在相当大的程度上改变纳米线阵列的各向异性 .

Structure and morphology of single-crystalline hep Co nanowires fabricated by electrodeposition were investigated in detail by various x-ray diffraction methods. The results confirm that the Co nanowires can be deposited in single crystalline with the same crystal orientation of [100] along the longitudinal axes. The arrays were composed from those nanowires preferentially in [100] direction with very high parallelity, but the [001] axis of the nanowires randomly lies in the array plane. By slightly higher depositing voltage, some twisted deformation could happen in the nanowires with chiral behaviour. A twisted model has been brought forward to explain the experimental results. Magnetization properties measured by superconducting quantum interference device magnetometer at 300K indicated that the twisted lattices in the wire significantly affected the anisotropy of the nanowires due to the magnetoelastic effect, and consequently, the magnetic easy axis can be tuned to the longitudinal direction effectively.