【摘要】：近年來,研究發(fā)現(xiàn)復合結(jié)構(gòu)磁性材料中存在著多種磁相互作用,材料的幾何結(jié)構(gòu)、磁性層的變化等均會引起材料內(nèi)部相互作用機制的不同,進而影響材料的使用。另一方面,由于巨磁阻抗(GMI)效應在低場范圍表現(xiàn)出極高的靈敏度,不僅可以在弱磁傳感器等領域中得到應用,也被發(fā)展為復雜結(jié)構(gòu)磁性材料的研究手段之一。為了進一步闡明復合結(jié)構(gòu)絲內(nèi)的相互作用,本文利用磁控濺射法在Cu絲襯底上制備了Ni_(80)Fe_(20)鍍層,通過改變鍍層厚度、層數(shù),設計了具有不同幾何結(jié)構(gòu)的樣品,重點考察了多磁性層復合結(jié)構(gòu)絲內(nèi)的磁偶極相互作用機制及其對材料GMI效應的影響。本文的主要工作包括以下幾個方面:一、制備了Ni_(80)Fe_(20)/Cu單磁性層復合結(jié)構(gòu)絲,系統(tǒng)地研究了鍍層厚度對磁阻抗效應的影響。發(fā)現(xiàn)最大阻抗比隨Ni_(80)Fe_(20)層厚度的增加呈現(xiàn)出先增大后減小的變化規(guī)律,與之對應的軸向偏置場呈先減小后增大的趨勢,推測該現(xiàn)象與制備過程中產(chǎn)生的剩余壓應力以及鍍層表面形貌有關。Ni_(80)Fe_(20)層厚度為485nm時,復合結(jié)構(gòu)絲的最大磁阻抗比最大,偏置場最小。由此可知,可以通過改變鍍層厚度來控制鍍層的磁性能。二、雙磁性層Ni_(80)Fe_(20)(tout)/Ni_(80)Fe_(20)(tin)/Cu復合結(jié)構(gòu)絲的制備和磁性能研究。通過改變樣品內(nèi)外磁性層的厚度,制備了具有內(nèi)縱向外環(huán)向、雙環(huán)向各向異性磁結(jié)構(gòu)的復合結(jié)構(gòu)絲。結(jié)果發(fā)現(xiàn)內(nèi)縱向外環(huán)向樣品的磁阻抗曲線呈雙峰結(jié)構(gòu),與總厚度相同的單磁性層復合結(jié)構(gòu)絲磁阻抗曲線幾乎重合,說明這種情況下層間相互作用弱。雙環(huán)向磁結(jié)構(gòu)樣品的磁阻抗曲線呈現(xiàn)出四峰結(jié)構(gòu),且內(nèi)鍍層的有效各向異性場Hk比同厚度的單磁性層樣品的Hk大。這主要由于內(nèi)外層磁結(jié)構(gòu)相似時,層間相互作用強,從而引起了鍍層各向異性場的變化。三、固定單層的濺射時間10分鐘不變,多磁性層[Ni_(80)Fe_(20)]n/Cu復合結(jié)構(gòu)絲的制備和磁性能研究。實驗結(jié)果表明,隨著鍍層層數(shù)的增加,復合結(jié)構(gòu)絲的最大磁阻抗比明顯增大。n=1時,鍍層具有縱向磁各向異性,這與鍍層的剩余應力和表面形貌有關;而n=2,3,4時,鍍層具有環(huán)向磁各向異性,層間的相互作用隨層數(shù)的增加而增強,對磁阻抗曲線中Hp的抑制作用也增強。
[Abstract]:In recent years, it has been found that there are many kinds of magnetic interactions in the magnetic materials with composite structures. The geometric structure of the materials and the change of the magnetic layer will lead to the difference of the internal interaction mechanism of the materials, which will affect the use of the materials. On the other hand, because the giant magnetoimpedance (GMI) effect shows very high sensitivity in the low field range, it can not only be used in the field of weak magnetic sensors, but also developed into one of the research methods of magnetic materials with complex structures. In order to further elucidate the interaction in composite wire, Ni_ (80) Fe_ (20) coating was prepared on Cuwire substrate by magnetron splashing. By changing the thickness and number of layers, samples with different geometric structures were designed. The magnetic dipole interaction mechanism in multi-magnetic composite wire and its effect on GMI effect were investigated. The main work of this paper includes the following aspects: first, Ni_ (80) Fe_ (20) / Cu single magnetic layer composite structure wire was prepared, and the effect of coating thickness on magnetoimpedance effect was studied systematically. It is found that the maximum impedance ratio increases at first and then decreases with the increase of the thickness of Ni_ (80) Fe_ (20) layer, and the corresponding axial bias field decreases at first and then increases. It is inferred that this phenomenon is related to the residual compressive stress produced in the preparation process and the surface morphology of the coating. When the thickness of Ni _ (80) Fe_ (20) layer is 485nm, the maximum magnetoresistive ratio of the composite structural wire is the largest and the bias field is the smallest. Therefore, the magnetic properties of the coating can be controlled by changing the thickness of the coating. 2. Preparation and magnetic properties of double magnetic layer Ni_ (80) Fe_ (20) (tout) / Ni_ (80) Fe_ (20) (tin) / Cu) composite structural wires. By changing the thickness of the magnetic layer inside and outside the sample, the composite structure wire with inner and longitudinal circumferential and double circumferential anisotropy magnetic structure was prepared. The results show that the magnetoimpedance curve of the inner and longitudinal circumferential samples is bimodal, which almost coincides with the magneto-impedance curve of the single magnetic layer composite structure with the same total thickness, which indicates that the interlayer interaction is weak in this case. The magnetoimpedance curve of the double annular magnetic structure sample shows a four-peak structure, and the effective anisotropy field Hk of the inner coating is larger than that of the single magnetic layer sample of the same thickness. This is mainly due to the strong interlaminar interaction when the magnetic structure of the inner and outer layers is similar, which leads to the change of the anisotropy field of the coating. 3. The preparation and magnetic properties of [Ni_ (80) Fe_ (20)] n/Cu composite structural wires with fixed monolayer for 10 minutes were studied. The experimental results show that with the increase of the number of layers, the maximum magnetoimpedance ratio of the composite structural wire increases obviously. When n = 1, the coating has longitudinal magnetic anisotropy, which is related to the residual stress and surface morphology of the coating, while at n 鈮，

本文編號：2510918