NiFe_2O_4纳米线阵列的制备与磁性

Fabrication of NiFe_2O_4 nanowire arrays and its magnetic properties

在氧化铝模板的纳米孔洞中 ,用电化学的方法沉积铁镍合金纳米线 ,经过 5 5 0℃ 30h氧化处理 ,成功制备出NiFe2 O4 纳米线阵列 .分别用扫描电子显微镜 (SEM)、透射电子显微镜 (TEM)、x射线衍射仪 (XRD)和振动样品磁场计 (VSM)对样品的形貌、晶体结构和磁学性质进行了表征测试 .SEM和TEM观察结果显示氧化铝模板的孔洞分布均匀 ,孔心距约为 110nm ;纳米线的直径约为 70nm .XRD显示纳米线阵列的物相结构为NiFe2 O4 ;VSM测试结果表明 ,NiFe2 O4 纳米线阵列膜的易磁化方向垂直于膜面 .当垂直磁化时磁滞回线的矩形比约为 0 5 ,矫顽力为 4 1×10 3A m ,比氧化处理前的铁镍合金纳米线阵列都有显著提高 .

Arrays of NiFe2O4 nanowires were prepared by using porous anodic aluminum oxide(AAO) membrane as the template. For the preparation of the ferrite nanowires, Ni-Fe alloy nanowires were electrodeposited into the pores of the AAO membranes. The atomic ratio is about Ni:Fe = 1:2 which can be detected by engergy dispersive spectroscopy. X-ray diffraction study showed the pure phase of NiFe2O4 after anodization. SEM and TEM studies showed the diameters of the pores and the nanowires are all about 70 nm. The vibrating sample magnetometer studies of the nanowire arrays showed the anisotropic magnetic properties before and after anodization. Coercivity and squareness ratio have been improved apparently in the NiFe2O4 nanowires arrays.