Phase Transformation Seen Through"Millikelvin-Stabilized Cell"―Detection by X-ray Diffraction―

通过“毫开尔文稳定池”观察相变——X射线衍射检测——

• 批准号: 10640317
• 负责人: YOSHIMURA Yukio
• 金额: $ 2.11万
• 依托单位: Ritsumeikan University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640317/
• 关键词: simultaneous temperature, DC calorimeter and X-ray diffraction measurements; structural phase transition; "millikelvin-stabilized cell"; phase transition of CsPbClィイD23ィエD2; phase transitionof BaTiOィイD23ィエD2; X線回折実験; CsPbCl_3の相転移; BaTiO_3の相転移; 温度-

A Simple and versatile"millikelvin-stabilized cell" has been developed to investigate phase transformation stage in solid precisely. It can be used as a fine DC calorimeter and also, by mounting on a goniometer head, as an X-ray diffraction cell with a function of sensing thermal anomaly. When applied to the well known 320 K phase transformation in CsPbClィイD23ィエD2, it was found that it occurs not in a single-stage but in a hyperfine multistage in the temperature range of approximately 0.1 K.The results required a reinterpretation of the mechanism on the successive phase transition of the crystal. In order to make clear the hyperfine multistage transition, we have reexamined the phase changes of the crystal over wide temperature range, 340 K-90 K, by means of single crystal X-ray photographic method. On cooling from room temperature, it was found that at about 265K, an abrupt increase of intensity was observed at 0 k 1+ 1/2 superlattice reflections corresponding to the X-point in the cu … More bic Brilloun zone. With lowering temperature further to 200 K, another abrupt increase of intensity was observed at h+1/2 k+1/2 1+1/2 superlattice reflections which correspond to the R-point. The anomaly at the 200K, although accompanies with conspicuous splitting of the h k 1Bragg spots along [010]c* direction, weak spots without splitting were still observed. These facts indicated that a coexistence of two crystal forms exists in the lowest temperature phase below 200 K. One is a monoclinic form and the other is tetragonal one. The results in this study suggests that the crystal undergoes two series of successive structural changes starting from the superfine anomalies at the 320 K transition. One is 320―315―310 K transition series (series" II") which is related to the so called soft phonon condensation theory, and the other is 320―265―200 K transition series, series "I", which is however dominant in the specimen.The 408 K phase transformation in BaTiOィイD23ィエD2 by means of "millikelvin-stabilized cell" was also revealed to occur in multistage. An anomalous transition was also detected in (KCN)x(KBr) ィイD21-xィエD2 mixed crystal in advance study on the phase transition. Application of the "millikelvin-stabilized cell" to the precise study on the phase transition is now planned on these crystals. Less

一种简单且通用的“毫开尔文稳定池”已被开发出来，用于精确研究固体中的相变阶段，它可以用作精细的直流量热计，也可以通过安装在测角仪头上，用作带有温度计的 X 射线衍射池。当应用于众所周知的 CsPbCl 的 320 K 相变时，发现它不是单阶段发生的，而是超精细的。大约0.1 K的温度范围内的多阶段。结果需要重新解释晶体的连续相变机制。为了弄清楚超精细的多阶段转变，我们重新检查了晶体在宽温度范围内的相变。 ，340K-90K，通过单晶X射线照相法，从室温冷却后发现，在265K左右，在0k 1+处观察到强度的突然增加。 1/2 超晶格反射对应于 cu … More bic Brilloun 区中的 X 点，随着温度进一步降低至 200 K，在 h+1/2 k+1/2 1+1/ 处观察到强度的另一个突然增加。 2 个超晶格反射，对应于 200K 处的 R 点，尽管伴随着 hk 1Bragg 斑点的明显分裂。 [010]c*方向，仍然观察到没有分裂的弱点，这些事实表明在200K以下的最低温度相中存在两种晶型的共存。一种是单斜晶型，另一种是四方晶型。这项研究表明，晶体从320 K转变处的超细异常开始经历了两个连续的结构变化，一个是320-315-310 K转变系列（系列”）。 II”），与所谓的软声子凝聚理论相关，另一个是 320-265-200 K 转变系列，系列“I”，但它在样本中占主导地位。BaTiO D23D2 中的 408 K 相变通过“毫开尔文稳定细胞”的手段也被发现发生在多阶段中，并且在 (KCN)x(KBr) 中也检测到了异常转变。 D21-xD2混合晶体的相变研究目前正在计划应用“毫开尔文稳定池”对这些晶体进行精确的相变研究。

项目成果

Y.Yoshimura, T.Okazaki, T.Tsuruta, S.Fujita, A.Ishikawa, N.Tsuda and H.Iwasaki: "X-Ray Diffraction Study on the Structural Phase Transitions of (KCN)ィイD2xィエD2(KBr)ィイD21-xィエD2 Mixed Crystals"Phys.Soc.Jpn.. Vol. 68. 3292-3302 (1999)

Y.Yoshimura、T.Okazaki、T.Tsuruta、S.Fujita、A.Ishikawa、N.Tsuda 和 H.Iwasaki：“(KCN) KBr)IID21-xIED2 混合晶体结构相变的 X 射线衍射研究“Phys.Soc.Jpn.. Vol. 68. 3292-3302 (1999)

K.Tozaki, Y.Yoshimura, A.Kojima, C.Ishii, O.Izuhara, K.Yamada, S.Koyama and H.Iwasaki: "Phase Transformation Seen through "Millikelvin-stabilized Cell"― Detection of "Multistage Transformation" in a Small Temperature Range"The Japan Institute of Metals. J

K. Tozaki、Y. Yoshimura、A. Kojima、C. Ishii、O. Izuhara、K. Yamada、S. Koyama 和 H. Iwasaki：“通过“毫开尔文稳定电池”看到的相变——“多级相变”的检测在小温度范围内”日本金属研究所。J

東崎 健一: "Phase Transformation Seen through "Millikelvin-stabilized Cell" -Detection of"Multistage Transformation"in a Small Temperature Range"The Japan Institute of Metals. 1433-1436 (1999)

Kenichi Higashizaki：“通过“毫开尔文稳定池”观察到的相变 - 小温度范围内“多级相变”的检测”日本金属研究所 1433-1436 (1999)。

吉村 幸雄: "X-Ray Diffraction Study on the Structural Phase Transitions of (KCN)_x(KBr)_<1-x> Mixed Crystals"J. Phys. Soc. Jpn.. Vol.68. 3292-3302 (1999)

Yukio Yoshimura：“(KCN)_x(KBr)_<1-x> 混合晶体的结构相变的 X 射线衍射研究”J. Jpn.. Vol. 3292-3302 (1999)。

K.Tozaki, C.Ishii, Y.Yoshimura, H.Iwasaki, A.Kojima 他: "“Millikelvin-stabilized cell" for X-ray diffraction measurements with a function of sensing thermal anomalies." Review of Scientific Instruments. 69. 3298-3299 (1998)

K. Tozaki、C. Ishii、Y. Yoshimura、H. Iwasaki、A. Kojima 等人：“用于 X 射线衍射测量的“毫开尔文稳定池”，具有感测热异常的功能。” 69. 3298-3299 (1998)