Physics Division, PINSTECH, P,O, Nilore, Islamabad, Pakistan.
Nanoscale Res Lett. 2010 Apr 23;5(7):1111-7. doi: 10.1007/s11671-010-9610-5.
Cobalt nanowires with controlled diameters have been synthesized using electrochemical deposition in etched ion-track polycarbonate membranes. Structural characterization of these nanowires with diameter 70, 90, 120 nm and length 30 μm was performed by scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction techniques. The as-prepared wires show uniform diameter along the whole length and X-ray diffraction analysis reveals that [002] texture of these wires become more pronounced as diameter is reduced. Magnetic characterization of the nanowires shows a clear difference of squareness and coercivity between parallel and perpendicular orientations of the wires with respect to the applied field direction. In case of parallel applied field, the coercivity has been found to be decreasing with increasing diameter of the wires while in perpendicular case; the coercivity observes lower values for larger diameter. The results are explained by taking into account the magnetocrystalline and shape anisotropies with respect to the applied field and domain transformation mechanism when single domain limit is surpassed.
采用电化学沉积法在刻蚀的离子通道聚碳酸酯膜中合成了具有可控直径的钴纳米线。通过扫描电子显微镜、高分辨率透射电子显微镜和 X 射线衍射技术对直径为 70、90 和 120nm 且长度为 30μm 的这些纳米线进行了结构表征。所制备的纳米线在整个长度上表现出均匀的直径，X 射线衍射分析表明，随着直径的减小，这些纳米线的[002]织构变得更加明显。纳米线的磁特性研究表明，在相对于施加磁场方向的平行和垂直取向的情况下，方形度和矫顽力有明显的差异。在平行施加磁场的情况下，发现矫顽力随纳米线直径的增加而减小，而在垂直情况下，较大直径的矫顽力观察到较低的值。考虑到相对于施加磁场的磁晶各向异性和形状各向异性以及超过单畴极限时的畴转变机制，可以解释这些结果。
