Study of Microscopic Pattern Formation in Structural Phase Transition by Electron Microscopy

结构相变微观图案形成的电子显微镜研究

• 批准号: 04402051
• 负责人: YAMAMOTO Naoki
• 金额: $ 22.27万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04402051/
• 关键词: Electron Microscopy; Structural Phase Transition; Pattern Formation; Commensurate-Incommensurate Phase Transition; Discommensuration

The purpose of this research is to study structural and physical properties of microscopic patterns arising in several structural phase transitions, and to find the dynamical properties of their pattern formations by means of an electron microscope with a nanometer-size probe. The main results are divided into the following three categories.1. Pattern formation in commensurate-incommensurate phase transitionPattern evolution of the discommensuration(DC) lattices during the C-IC phase transitions in Rb2ZnCl4 and BaZnGeO4 was observed and their properties were studied from the analyzes of the dark field images and also the diffuse intensity profiles in the diffraction patterns, using the TV camera system and the imaging plate system. The creation and annihilation of stripples and antistripples were seen and the interactions between stripple and planer DC were observed, which accompany the rearrangements of DCs.2. New founding in several phase transitionsIt is found that the electron beam … More irradiation induces phase transition in BaZn GeO4, and at least three distinct phases were observed to appear. In Pb3(PO4)2 the high resolution image using the diffuse scattering was taken above the ferroelstic phase transition temperature, which indicates the existence of microdomains of the ferroelastic phase. In the C-IC phase transition of Ba2NaNb5015 the ferroelastic domains of the order of 10nm in size are found to be created in the IC phase, which result in the tetragonal symmetry and the qusi2-q state of the IC phase. The IC-C phase transition and the memory effect were studied through the observation of DC and ferroelastic domain wall motion.3. Physical measurement of microscopic regionWe try to develop the method to measure physical properties of nanoscale region as well as the structural properties obtained from the electron microscopic observation. It is found that the Cherenkov and transition radiation detected by the light collection system using a finely converged electron beam will provide information of the dielectric function of a nanoscale region. Less

本研究的目的是研究在几种结构相变中产生的微观图案的结构和物理性质，并通过具有纳米尺寸探针的电子显微镜来发现它们的图案形成的动力学性质。主要研究结果分为以下三大类.利用电视摄像系统和成像板系统，通过对衍射图样中的暗场图像和漫射强度分布的分析，观察了Rb_2 ZnCl_4和BaZnGeO_4在C-IC相变过程中的位错（DC）晶格的图样演化，并研究了它们的性质。观察到带状和反带状的产生和湮灭，以及带状DC和平面DC之间的相互作用，伴随着DC的重排.在几种相变中的新发现发现， ...更多信息 辐照诱导BaZnGeO 4的相变，并观察到至少出现三个不同的相。在Pb_3（PO_4）_2中，在铁弹相变温度以上拍摄了使用漫散射的高分辨率图像，这表明铁弹相的微畴的存在。在Ba_2NaNb_5O_（15）的C-IC相变中，IC相中产生了尺寸约为10 nm的铁弹畴，导致了IC相的四方对称性和准Si ~ 2-q态。通过对直流电和铁弹畴壁运动的观察，研究了IC-C相变和记忆效应.微观区域的物理测量我们尝试开发测量纳米区域的物理性质以及从电子显微镜观察获得的结构性质的方法。结果发现，切伦科夫和过渡辐射检测的光收集系统，使用一个精细的会聚电子束将提供信息的纳米尺度区域的介电函数。少

项目成果

S.Mori: "Memory effect,defect-density-wave,and related microstructure in an incommensurate phase of barium-sodium-niobate" Phys.Rev.B. 51. 51-54 (1995)

S.Mori：“铌酸钠不通约相中的记忆效应、缺陷密度波和相关微观结构”Phys.Rev.B。

N.Yamamoto: "Incommensurate-Commensurate Phase Transition of BaZnGeO_4 Studied by Electron Microsoopy and Diffraction" Journal of The Physical Society of Japan. 61. 3178-3188 (1992)

N.Yamamoto：“通过电子显微镜和衍射研究 BaZnGeO_4 的不相称相变”日本物理学会杂志。

山本直紀: "遷移放射" 固体物理. 29. 1-13 (1994)

山本直树：“过渡辐射”固体物理学。29. 1-13 (1994)

山本 直紀: "電子顕微鏡法による誘電体の相転移、不整合構造の研究" 日本結晶学会誌. 34. 1-10 (1992)

Naoki Yamamoto：“通过电子显微镜研究介电材料的相变和失配结构”日本晶体学会杂志 34. 1-10 (1992)。

N.Yamamoto: "Electron Beam lnduced Phase Transition of BaZnGeO_4" Proc.13th lntern.Conf.Electron Microscopy. 2. 553-554 (1994)

N.Yamamoto：“BaZnGeO_4 的电子束诱导相变”Proc.13th lntern.Conf.Electron Microscopy。