Si/Co/Cu/Co多层膜中巨磁电阻效应及与微结构的关系

用超高真空电子束蒸发方法在Si（100）衬底上制备了Si／Co／Cu／Co多层膜。发现当Si层厚度达到0．9nm时，多层膜中开始出现较强的平面内各向异性巨磁电阻效应。在Si1．5nm／Co 5nm／Cu3nm／Co5nm多层膜中，作者在其易轴上得到了5．5％的巨磁电阻值和0．7％／Oe的磁场灵敏度。用X射线衍射和透射电镜研究了si／Co界面之间的相互扩散，发现在Si层与Co层间形成了Co—Si化合物层，这个硅化物界面层诱导了其上的Co／Cu／Co三明治膜中的平面内磁各向异性乃至整个多层膜的平面内各向异性巨磁电阻效应。原子力显微镜表面形貌分析表明，随Si层厚度增大，Co／Cu／Co三明治膜的界面平整度得到改善，从而使巨磁电阻值增大。

Anisotropic GMR Effect in Si/Co/Cu/Co Multilayers and Its Correlation with Microstructure

The Si/Co/Cu/Co multilayers are prepared by the ultra-high vacuum electron-beam evaporation on the Si(100) substrate.It is found that an obvious in-plane anisotropic giant magnetoresistance(GMR) effect is appeared in multilayers when the Si layer is increased to 0.9 nm.A GMR of 5.5% and a high field sensitivity of 0.7%/Oe along the easy axis in Si 1.5 nm/Co 5 nm/Cu 3 nm/Co 5 nm multilayers are obtained.The interdiffusion at Si and Co interfaces is investigated by X-ray diffraction(XRD) and transmission electron microscopy(TEM).A cobalt silicide layer is found to be formed at the interface,which is thought to induce the in-plane magnetic anisotropy in the Co/Cu/Co sandwiches grown on it so that the in-plane anisotropic GMR effect in the multilayers.Analysis of the atomic force microscope(AFM) images also demonstrates that the interface flatness of Co/Cu/Co sandwiches is improved with increasing Si layer thickness,thus resulting in an enhanced GMR effect.