Some Bristol–Prague explorations in x-ray topography
Some Bristol–Prague explorations in x-ray topography
复制标题
布里斯托尔-布拉格 X 射线地形学的一些探索
DOI：
10.1088/0022-3727/38/10a/001
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. R. Lang
中科院分区：
文献类型：
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作者：
A. R. Lang
本文简要记载了物理研究所，捷克科学院和H H威尔斯物理实验室之间的长期和富有成效的合作。它开始于1962年初，米莱娜·波尔卡罗娃对布里斯托的短暂访问。最初的目标，成功地实现了，是映射的位错在熔融生长的单晶体的Fe-Si合金的透射形貌。一个新的副产品是在（110）和（112）取向制备的样品板的内部磁畴结构的X射线形貌观察。在所研究的含Si约3wt%的合金中，易磁化方向为100 °，畴界为180°或90°布洛赫壁。后一种壁可以产生强的X射线衍射对比度，但预期180°壁没有对比度。在（110）板中，X射线形貌显示了包含90°壁的复杂内部畴结构，其中一些以前在胶体图案（Bitter图案）的光学显微照相证据中未被怀疑。这些结构的某些细节至今仍是一个谜！在（112）样品中，其中没有易磁化方向位于板表面中，样品填充有畴的层次结构，朝着表面的尺度减小，以最小化由于自由磁极引起的静磁能。然而，在（112）板厚度小于20 μm的情况下，X射线形貌图记录的内部畴结构足够简单，可以解释其主要特征。这是由F C弗兰克在20世纪60年代初实现的，但直到1993年才出版！在1968年访问布里斯托的Polcarová它被发现，在适当的衍射条件下，x射线地形对比度从180°布洛赫墙壁是刚刚检测。这一发现直到1991年才发表。最近的工作与布拉格标本应用同步加速器X射线网状在达雷斯伯里，表明这种技术可以用于信息与轻度变形的铁硅双晶体。1967年，布里斯托发明了一种非常不同的方法，通过将一块晶体板叠加在另一块晶体板上来产生X射线莫尔条纹。这个项目得益于捷克的合作，通过J Brádler的巧妙参与，从布拉格休假。
This paper briefly chronicles a long-standing and productive collaboration between the Institute of Physics, Czech Academy of Science and the H H Wills Physics Laboratory. It began in early 1962 with a brief visit to Bristol by Milena Polcarová. The initial aim, successfully achieved, was the mapping by transmission topography of dislocations in melt-grown single crystals of a Fe–Si alloy. A novel by-product was the x-ray topographic observation of internal magnetic domain structures in specimen plates prepared in both (110) and (112) orientations. In the alloy studied, which contained about 3 wt% Si, the directions of easy magnetization are ⟨ 100 ⟩, and domain boundaries are either 180° or 90° Bloch walls. The latter walls can generate strong x-ray diffraction contrast, but no contrast from 180° walls is expected. In the (110) plates x-ray topography revealed complex internal domain structures containing 90° walls, some previously unsuspected on evidence of optical micrography of colloid patterns (Bitter patterns). Certain details of these structures remain a puzzle to this day! In (112) specimens, in which no direction of easy magnetization lies in the plate surface, the specimen is filled with a hierarchy of domains, diminishing in scale towards the surfaces in order to minimize magnetostatic energy due to free poles. However, in (112) plate thicknesses less than ∼20 µm, x-ray topographs recorded internal domain structures sufficiently uncomplicated for their main features to be interpreted. This was achieved by F C Frank in the early 1960s, but not published till 1993! During a 1968 visit to Bristol by Polcarová it was discovered that under appropriate diffraction conditions x-ray topographic contrast from 180° Bloch walls was just detectable. This finding was not published till 1991. More recent work with Prague specimens has applied synchrotron x-ray reticulography at Daresbury, showing that this technique can be informatively used with lightly-deformed Fe–Si bicrystals. A very different enterprise was the Bristol method of producing x-ray moiré patterns by superposing one crystal plate upon another, achieved in 1967. This project gained from Czech collaboration through the skilful participation of J Brádler, on leave from Prague.