电沉积Ni纳米线阵列及其磁学性能研究

为了解决因受阳极氧化铝(AAO)孔道直径限制导致合成的金属纳米线尺寸单一、磁性受限的问题,采用二次阳极氧化法制备了不同孔径的阳极氧化铝(AAO)模板,依据模板辅助电沉积法,在不同孔径AAO模板内生长了Ni纳米线阵列,利用SEM,TEM,XRD和EDS等技术对制备的Ni纳米线阵列形貌、微观结构和成分进行表征,通过物理性能测试系统(PPMS)研究了Ni纳米线的磁学性能。结果表明:Ni纳米线的生长机制是交流电正半周期Ni~(2+)还原与负半周期Ni原子溶解的共同作用;Ni纳米线具有磁各向异性,随着直径的增大,Ni纳米线的易磁化方向由平行于纳米线轴线方向逐渐转变为垂直于纳米线的方向,易磁化方向的转变是由有效各向异性场和磁畴结构随纳米线直径的改变而导致的。研究电沉积Ni纳米线阵列及其磁学性能,可为深入研究交流电沉积法制备磁性纳米线的生长机制和磁性纳米线的磁化机理提供理论和实验依据,为拓宽纳米线的应用领域奠定基础。

Electrodeposition of Ni nanowire arrays and their magnetic properties

In order to solve the problem that the size of the synthesized metal nanowires is single and the magnetic property is limited due to the limitation of the diameter of the anodic aluminum oxide (AAO) pore,anodic alumina (AAO) templates with different pore sizes were prepared by twice anodic oxidation method, and then Ni nanowire arrays were grown in AAO templates with different pore sizes by template-assisted electrodeposition method.The morphology, microstructure and composition of the prepared Ni nanowire arrays were characterized by SEM, TEM, XRD and EDS techniques. The magnetic properties of Ni nanowires were investigated by physical property measurement system (PPMS).The results show that the growth mechanism of Ni nanowires is the interaction between the reduction of positive half period Ni2+ by alternating current and the dissolution of negative half period Ni atoms. Ni nanowires have magnetic anisotropy, and with the increase of the diameter, the easy magnetization direction of Ni nanowires gradually changes from parallel to the axis of the nanowire to perpendicular to the axis of the nanowire. The change of easy magnetization direction is caused by the change of the effective anisotropic field and the magnetic domain structure with the diameter of the nanowire.The study of electrodeposition Ni nanowire arrays and their magnetic properties can provide theoretical and experimental basis for further study of the growth mechanism and magnetization mechanism of magnetic nanowires prepared by alternating current electrodeposition, it lays a foundation for widening the application field of magnetic nanowire.