CoxCu1-x复相纳米线阵列的制备及其磁性的研究

利用电化学沉积方法在同一种富Co²⁺溶液Co²⁺/Cu²⁺=10∶1中，利用不同的沉积电位成功地制备了一系列不同成分(x=0.38—0.87)和复合相结构的Co_xCu_1-x纳米线阵列.发现随着纳米线中Cu含量的变化，Co_xCu_1-x纳米线的复相结构随之发生规律的变化，最终导致纳米线的磁性也随之规律的变化.随着纳米线中Cu含量的不断增加，一部分Cu与Co形成面心立方结构(fcc)的CoCu固溶体，减弱了磁晶各向异性与形状各向异性的竞争，从而提高样品的方形度；一部分Cu以fcc结构的Cu单质的形式存在于纳米线中，并随着Cu颗粒大小的不同分别起到破坏磁晶各向异性和钉扎畴壁的作用，从而增加纳米线的方形度和矫顽力.对比不同成分的样品，发现Co_xCu_1-x纳米线的方形度和矫顽力的最大值分别出现在Co₇₅Cu₂₅和Co₆₀Cu₄₀中，并且由于其特殊的复相结构致使它们的值要好于相同直径的单相结构的结果. 关键词： 纳米线 电化学沉积 磁性

Fabrication and magnetic properties of CoxCu1-x composite nanowire arrays

A series of composite structured Co_xCu_1-x(x=0.38—0.87) nanowire arrays have been successfully deposited in the same Co²⁺/Cu²⁺=10∶1 solution by applying various depositing potentials. We found that the structures of Co_xCu_1-x composite nanowires regularly changed with increase of Cu content, thus causing regular change of the magnetic properties of CoCu nanowires. With the percent content of Cu increasing, part of Cu and Co form metastable face-centred cubic (fcc) CoCu solid solution which decreases the competition between the crystallographic anisotropy and shape anisotropy and improves the squareness of CoCu nanowires; the remaining part of Cu exists in the nanowires as fcc Cu crystals which destroy the crystallographic anisotropy and increases the pinning of domain walls, thus improves the squareness and coercivity of CoCu nanowires. Comparing Co_xCu_1-x nanowires of different compositions, we found that the nanowires have their maximum of the squareness (M_r/M_s) and coercivity (H_c) values for Co₇₅Cu₂₅ and Co₆₀Cu₄₀, respectively. Because of the special composite structures, the values exceed those of single phase CoCu nanowire with the same diameter.