【作者】 吴士蓉；

【导师】 袁望治；

【作者基本信息】 华东师范大学 ， 凝聚态物理， 2005， 硕士

【摘要】 本文用化学镀方法制备NiFeP/CuBe复合结构丝,并对不同方式退火后样品的巨磁阻抗效应(Giant Magneto-impedance Effect,简称GMI)进行了比较系统的研究,结果表明退火方式所产生的不同磁结构是影响样品巨磁阻抗效应的重要原因。1. 用化学镀方法在CuBe丝上成功地沉积出NiFeP镀层,制备了NiFeP/CuBe复合结构丝。2. 为得到最佳的巨磁阻抗效应,研究了样品制备的工艺条件对样品巨磁阻抗效应的影响。化学镀浴中Ni2+和Fe2+浓度的变化对NiFeP镀层的成分影响很大,在工艺条件为FN=[Fe2+]/[Ni2++Fe2+]=0. 7,NiFeP镀层成分为Ni79Fe15P6。CuBe丝在镀液中镀制1小时,样品NiFeP镀层的厚度大约为1. 5μm。3. 化学镀NiFeP薄膜对退火温度比较敏感。随着温度的增加,样品从非晶到纳米晶,晶粒进一步长大,同时晶体的择优取向也会发生变化。4. 退火方式对样品性能有很大的影响,电流应力退火和电炉退火不能提高样品的磁阻抗效应;而电流退火能使样品产生圆周磁各向异性,从而大幅度提高样品的巨磁阻抗效应。5. 一定条件下进行电流退火能使样品的磁结构产生圆周各向异性,从而提高样品的巨磁阻抗效应。当退火电流大于2. 4A时,样品的巨磁阻抗效应相对于制备态表现出了明显的提高。在2. 8A退火2分钟的条件下,驱动频率为475KHz时,样品的阻抗值达到最大,53. 2%,同时在50KHz时,样品已经呈现出较大的磁阻抗效应,达到26. 5%。更多还原

【Abstract】 In this paper, we prepared the NiFeP/CuBe composited wires by electroless- deposition, and used different ways to anneal the samples. Then the giant magneto-impedance effect （GMI） of the NiFeP/CuBe composite wires were studied systemically. The results demonstrate that the different magnetic domain structures are important to the GMI effect of the composite wires.1, The NiFeP films are excel lently electro less-deposited on CuBe wire and the NiFeP/CuBe composite wire is hereby prepared.2, n order to get ideal GMI effect, the optimized condition of fabricating was studied. The composition of NiFeP film is dependent on the concentrations of Ni²⁺ and Fe²⁺ in NiFeP electroless-plating bath, which is vital to the GMI effect of the NiFeP/CuBe composite wires. The optimal conditions are as follow: FN = [Fe²⁺]/[Ni²⁺+Fe²⁺] = 0.7, and the composition of the composite wires is Ni₇₉Fe₁₅P₆. And when the CuBe wires were deposited for 1 hour in the bath, the thickness of the ferro-magnetic layer is about 1.5μm.3, Annealing techniques have great effects on the samples. DC Joule annealing can induce circular anisotropy, so as to increase the GMI effect of the samples; while stress annealing and annealed in a furnace can only induce longitudinal anisotropy, which will lead to the decrease of the GMI effect of the samples.4, NiFeP/CuBe samples are sensitive to the temperature. With the increase of the temperature, from anisotropy to nanocrystalline, and then the samples crystallized. Meanwhile, its prefered orientation changes.5, In certain condition, DC Joule annealing can induce circular anisotropy among the ferro-magnetic layer of the samples, thus increases the ratio of the GMI effect of the samples. When the current is lagerer than 2. 4A, the GMI effect of the samples enhance greatly. In the optimum condition tof annealing for 2minutes with 2.8A, when the drive frequency is 475KHz, the sample’s highest value is 53.2%And meanwhile, obvious MI effect of NiFeP/CuBe composite wire is observed with the value of 26.5% at 50kHz.更多还原