采用电化学沉积在多孔氧化铝模板中制备了NiCo/Cu多层结构纳米线,并使用扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征了纳米线的形貌和微观结构.透射电子显微镜的结果表明,通过控制阶梯电位时间,制备的铁磁层厚度为100 nm,非铁磁层厚度为10 nm.结合选区电子衍射技术(SAED)与X射线衍射分析技术(XRD),确定多层纳米线的晶格结构是面心立方(FCC).在分析多层纳米阵列的微观结构之后,使用振动样品磁强计(VSM)测量磁滞回线.结果表明,随着Co含量的增加,多层纳米线的矫顽力升高.当多层纳米线中Co含量为10%和30%时,易磁化轴垂直于纳米线,当Co含量为70%和90%时,易磁化轴平行于纳米线.最后,对纳米线磁化翻转机制进行微磁学模拟分析得出,当外加磁场垂直于纳米线时,磁化反转机制是形核机制;当外加磁场平行于纳米线时,磁化反转机制是卷曲机制.
The NiCo/Cu multilayer nanowires have been fabricated by the porous anodic aluminum oxide assisted electrodeposition.Then,scanning electron microscope (SEM) and transmission electron microscope (TEM) are used to analyze the morphology and nanostructure of the multilayer nanowire.The thickness of the ferromagnetic layer and the non-ferromagnetic layer are controlled to be 100 nm and 10 nm,respectively,by adjusting the deposition time.The results of selected area electron diffraction (SAED) and X-ray diffraction (XRD) show that the crystal structure of the nanowire is face center cubic (FCC) phase.After the microstructure characterization of the multilayer,the hysteresis loops are measured by a vibrating sample magnetometer (VSM).The results indicate that the coercivity of the multilayer nanowire increases with increasing the content of Co.The easy axis of the multilayer stays perpendicular when the content of cobalt is 10% and 30%,while the easy axis tend to be parallel to the nanowire when increasing the ratio of Co to 70% and 90%.At last,the magnetic reversal mechanism is tentatively analyzed by micro-magnetic simulation.The reversal mode is nucleation controlled when the applied field is perpendicular to the nanowire.And when the applied magnetic field is parallel to the nanowire,the magnetic reversal would be controlled by curling.