Preparation and Caracterization of Electrodeposited Magnetic Multilayrs

基于成核生长机理和实验观察，讨论了电沉积法制备原子控制Co/Pt和Co/Cu磁性多层膜的方法。对电沉积Co， Cu/Pt（111）超薄层的反射电子显微镜研究表明，在室温下，在几个到大约十个单层覆盖范围内，异质外延和同时多核多层生长，这取决于结晶过电位。横截面透射电镜观察、x射线衍射、俄歇和光电子能谱实验为电位控制下电沉积制备的Co/Pt和Co/Cu纳米多层结构的连续层组成调制提供了直接证据。多层膜的生长和结构取决于沉积过电位。在室温下，在含有10nm标称Cu间隔层厚度的（111）织构Co/Cu多层纳米结构中观察到超过20%的“巨”磁阻。这一数值几乎与先前报道的气相沉积多层材料的数值相当。进一步研究成核和生长的结晶动力学是提高纳米多层结构质量的必要条件。在精确结晶过电位和电流密度控制下的电沉积将是制备磁性多层材料的一项极具竞争力的技术，并且有可能创造出具有气相沉积无法获得的不同寻常磁性的多层结构。

Fabrication of atomically controlled Co/Pt and Co/Cu magnetic multilayrs by electrodeposition has been discussed on the basis of a nucleation-growth mechanism and experimental observations. Reflection electron microscopy studies of electrodeposited Co, Cu/Pt (111) ultrathin layrs have revealed a heteroepitaxial and simultaneous multinuclear multilayr growth in a range from seversl up to some ten monolayr coverages at room temperature, which has been dependent upon the crystallization overpotential. Cross-sectional transmission electron microscopy observations, X-ray diffraction, and Auger and photoelectron spectroscopy experiments have provided direct evidence for composition modulation across successive layrs in Co/Pt and Co/Cu nanometer-multilayred structures prepared by electrodeposition under potential control. The growth and structure of the multilayrs have been dependent upon the deposition overpotential. "Giant" magnetoresistance of more than 20% has been observed at room temperature in a (111) textured Co/Cu multilayred nanostructure containing a nominal Cu spacer layr thickness of 10 nm. This value is nearly comparable to those previously reported in vapor-deposited multilayrs. Further studies on the crystallization kinetics of nucleation and growth are necessary to obtain improved quality of the nanometer-multilayred structures. Electrodeposition under precise crystallization overpotential and current density control will be a highly competitive technique for the preparation of magnetic multilayrs, and has a potential to create multilayred structures exhibiting unusual magnetic properties previously unavailable by vapor-phase deposition.