同步辐射异常散射研究超薄金属多层膜

近些年来,巨磁电阻金属多层膜由于其在信息存储和其它传感器方面的应用而广受关注.但是,由于金属多层膜中每层厚度都很薄,界面及层内微结构研究很困难.本文介绍利用同步辐射异常散射技术和反射技术相结合,研究超薄金属多层膜中元素分布的原理,及其在不同系统中的应用.     

YBCO薄膜微结构的表征

用X射线衍射技术和扫描电镜详细表征了生长在Y-ZrO₂(YSZ)衬底上YBa₂Cu₃O_7-σ(YBCO)薄膜的微结构.结果发现,采用Eu₂CuO₄(ECO)做缓冲层,可以提高YBCO薄膜的质量,而不改变其超导性能.     

Erratum to “Accurate determination of film thickness by low-angle x-ray reflection”

Equation (6) in Chin. Phys. 09 0833 (2000) is corrected. All subsequent derivations were given based on the correct Eq. (6), so the conclusions in the paper are not affected by the errata.     

Ba TiO3/SrTiO3超晶格Bragg衍射及其理论模拟

用X射线全外反射掠入射衍射和通常Bragg衍射,研究了Ba TiO³/SrTiO³(BTO/STO)超晶格的界面应变.X射线衍射动力学理论用于模拟Bragg衍射.发现与一般半导体外延膜或超晶格不同,BTO/STO超晶格的垂直和水平晶格常数的关系不完全遵守四方畸变的规律.这种偏离可能与钙钛矿型氧化物材料的结构复杂性有关.     

ACCURATE DETERMINATION OF FILM THICKNESS BY LOW-ANGLE X-RAY REFLECTION

A modified Bragg law for straightforward determining the film thickness by low-angle X-ray reflection was derived based on the geometrical optical theory. We showed that this modified Bragg law and its inference formulae could be used to accurately determine the thickness of the monolayer or multilayer film. Furthermore, the modified Bragg law for determining the superlattice period presented earlier by others can be derived from the above modified Bragg law. The similar inference formulae were also given. The precision in determining the film thickness and/or superlattice period by the above formulae was discussed.