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

“简单和通用”millikelvin-稳定单元"已开发到可靠的阶段转换阶段。它可以用作一个精细的直流热量计，也可以安装在一个测角仪头部上，作为一个具有感应热异常功能的X射线分化细胞。当在CsPbCly D23 E D2中应用已知的良好320 K相位转换时，发现它不在一个单一阶段，但在接近0.1 K的温度范围内的超精细多相位转换的结果需要对晶体成功相位转换的机制进行重新解释。如果要清除超精细多阶段过渡，我们重新评估了晶体在宽温度范围内的相位变化， 340 K-90 K，是单晶体X射线摄影方法的意思。根据房间温度的冷却，发现在大约265 K的温度下，强度增加了，在0 k1 + 1/2的超晶格反射与X点对应 ... More Bic Brilloun Zone在低于200 K的温度下，另一个强度增加了在h+1/2k +1/21 +1/2超晶格反射与R点的正确性。200 K的反常现象，还有一个与h k1布拉格斑点周围有意识的splitting的伴侣[010]c* direction，没有splitting仍然被保留。这些事实表明，两种水晶形式在200 K以下温度最低阶段存在的共存。一个是单色的，另一个是四边形的。本研究中的结果，即水晶欺诈者两个系列成功的结构性变化从320 K过渡开始的超精细异常现象。一个是320 - 315 - 310 K transition series （series" II"）哪个是与so called soft phonon condensation theory相关的，而另一个是320 - 265 - 200 K transition series， series "I"，哪个是however dominant in the specimen。The 408 K phase transformation in BaTiO D23イエD2 by means of "millikelvin-stabilized cell" was aled to occur in multi？age。在（KCN）x（KBr）D21-x D2在阶段过渡研究中也检测到了一个异常过渡。“millikelvin-stabilized cell”的应用程序到phase transition is now planned on these crystals。Less（低）

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