权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Artificial fabrication and magnetic properties of non-equilibrium ordered alloys by monatomic layr control

单原子层控制非平衡有序合金的人工制造及其磁性能

基本信息

批准号：
08455316
负责人：
TAKANASHI Koki
金额：
$ 5.63万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

We have compared structural and magnetic properties of the Ll_0-type FeAu ordered alloy fabricated by monatomic layr control to those of Fe (x ML) /Au (x ML) superlattices, where ML represents monatomic layr thickness. X-ray diffraction peaks corresponding to the superlattice period of x+x=2x ML have been observed definitely both for x=integers and non-integers. The X-ray diffraction patterns can be simulated by the model assuming a complete layr-by-layr growth with strucutural coherence throughout the sample, indicating the formation of coherent layred structure. The perpendicular magnetic anisotropy energy has been estimated from the in-plane and perpendicular magnetization curves. The product of the perpendicular anisotropy energy K_* and the Fe layr thickness t_<Fe>, K_*・t_<Fe>, for x=integers, decreases linearly with increasing t_<Fe> as seen in many magnetic superlattices. The interface anisotorpy energy K_s evaluated from the linear relationship increases with x for 1<less than … More or equal>x<less than or equal>3, and saturates for x<greater than or equal>4, which is explained by an extended Neel model. For x=non-integers, on the other hand, K_*・t_<Fe> vs.t_<Fe> deviates from the linear relationship, and shows oscillatory behavior with a period of 1 ML.We consider that this is a consequence associated with the reduction in K_s due to the interface roughness for x=non-integers. This study provides the first discovery of the oscillatory perpendicular anisotropy in magnetic superlattices. Furthermore, FMR measurements have indicated that the in-plane fourfold anisotropy also oscillates as a function of t_<Fe> with a period of 1.ML.In order to elucidate the origin for the oscillatory magnetic anisotropies, more precise structure analyzes including high resolution TEM,EXAFS and in situ STM are necessary. Magnetooptical measurements also indicate the oscillation of the Kerr rotation for the photon energy less than 2.5 eV.For 1<less than or equal>x<less than or equal>8, in addition, prominent structure around 3-4 eV has been observed, suggesting the formation of quantum well states of 3d electrons in Fe layrs. Less

我们比较了单原子层控制制备的ll_0型FeAu有序合金与Fe (x ML) /Au （x ML）超晶格的结构和磁性能，其中ML表示单原子层厚度。x=整数和非整数的x+x=2x ML超晶格周期对应的x射线衍射峰已经被明确地观察到。该模型可以模拟样品的x射线衍射图，该模型假设样品完全逐层生长，结构相干性贯穿整个样品，表明形成了相干层状结构。根据平面内和垂直磁化曲线估计了垂直磁各向异性能。垂直各向异性能K_*与铁层厚度t_<Fe>、K_*·t_<Fe>的乘积在许多磁超晶格中随着t_<Fe>的增大而线性减小。从线性关系计算得到的界面各向异性能K_s在1< <…时随x增大，大于或等于>x<小于或等于bbb3，当x<大于或等于bbb4时达到饱和，这可以用扩展的Neel模型来解释。另一方面，对于x=非整数，K_*·t_<Fe> vs.t_<Fe>偏离线性关系，表现出周期为1 ml的振荡行为，我们认为这是由于x=非整数时界面粗糙度导致K_s减小的结果。本研究首次发现了磁超晶格中振荡垂直各向异性。此外，FMR测量表明，平面内的四重各向异性也作为t_<Fe>的函数振荡，周期为1 ml。为了阐明振荡磁各向异性的成因，需要进行更精确的结构分析，包括高分辨率TEM、EXAFS和原位STM。磁光测量还表明光子能量小于2.5 eV时克尔旋转振荡。对于1<或等于>x<或等于bbb8，在3-4 eV附近观察到明显的结构，提示三维电子在Fe层中形成了量子阱态。少