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

本文介绍了一种简单、多用途的“Millikelvin稳定池”，用于精确研究固态相变阶段。它既可用作精密的直流量热计，也可装在测角器头上用作具有热异常感测功能的X射线衍射池。当应用到众所周知的320 K相变在CsPbCl <$D23 <$D2，它被发现，它发生在一个单一的阶段，但在一个超精细的多阶段的温度范围约为0.1 K的结果需要重新解释的机制上的连续相变的晶体。为了弄清超精细多级相变，我们用单晶X射线照相方法重新研究了晶体在340 K-90 K宽温区的相变。从室温冷却后，发现在265 K左右，在0 k1 + 1/2超晶格反射处（对应于Cu中的X点）观察到强度的突然增加。 ...更多信息 bic Brilloun区。随着温度进一步降低到200 K，在h+1/2 k+1/2 1+1/2超晶格反射处观察到另一个强度的突然增加，其对应于R点。在200 K处的反常，虽然伴随着[010]c* 方向沿着1布拉格点的明显分裂，但仍观察到没有分裂的弱点。这些事实表明，在低于200 K的最低温度阶段存在两种晶型共存。一种是单斜晶型，另一种是四氢呋喃酮。研究结果表明，该晶体在320 K转变时经历了两系列连续的结构变化。一个是与软声子凝聚理论有关的320―315―310 K相变系列（系列”II”），另一个是占主导地位的320―265―200 K相变系列（系列“I”），BaTiO_xD_（23）BaTiO_xD_（23）D_2的408 K相变也是分阶段进行的。在对（KCN）x（KBr）∶ D21-x ∶ D22混晶相变的进一步研究中，也发现了一个反常的相变。现在计划在这些晶体上应用“millikelvin稳定细胞”来精确研究相变。少

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)。

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> 混合晶体结构相变的 X 射线衍射研究”J.Phys.Soc.Jpn.. Vol.68 (1999)。