磁场对模板法制备的Co纳米线结构和磁性的影响

在用二次氧化法制备的高度有序的氧化铝模板上通过交流电化学方法制备了Co纳米线阵列．研究了外加磁场及电解液pH值对纳米线生长的影响．在pH值为6.0和6.5的电解液中分别在不加磁场和沿纳米线轴向施加0.3 T磁场情况下制备了hcp结构的Co纳米线阵列．实验数据表明，沉积时外加磁场和调节pH值能有效影响纳米线中hcp结构的Co晶粒的易磁化轴沿纳米线长轴方向生长．由于晶粒的磁晶各向异性和纳米线沿长度方向的宏观形状各向异性叠加，制备的Co纳米线阵列具有高垂直各向异性，高矫顽力和较高矩形比．关键词：Co纳米线阵列织构磁性

Effects of applied magnetic field on microstructure and magnetic properties of template-based Co nanowire arrays

Arrays of Co nanowires were fabricated by ac electrochemical deposition of metal into high order anodic alumina templates prepared through two-step oxidation method. The effects of applied magnetic field and the pH value of the electrolyte on growth of nanowires were investigated. Arrays of Co nanowires of hcp structure were deposited in the electrolyte whose pH values are 6.0 and 6.5 without magnetic field, then 0.3 T magnetic field was applied along the long axis of nanowires. The experimental results show that external magnetic field and adjustment of pH value of the electrolyte impel the easy magnetization axis of the hcp Co grain to grow along length direction of nanowires. The Co nanowire arrays show higher perpendicular anisotropy, larger coercivity and high M/M_s because the superposition of the crystal anisotropy of hcp Co grains and shape anisotropy of nanowire along length direction.