Syntheses and Mechanism of Electric Conduction of 2-Dimensional Mixed Metal Chalcogenides

二维混合金属硫属化物的合成及导电机理

• 批准号: 62470060
• 负责人: ATAKE Tooru
• 金额: $ 3.84万
• 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 (B)
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-62470060/
• 关键词: AgCrS_2; CucrS_2; Ag_XCu_<1-X>CrS_2; NaCrS_2; Order-disorder phase transition; 相強磁性相転移; Ag_XCu_1_-_XCrS_2; 規則-不規則相転移; 反強磁性相転移; 混合導電体; 規則ー不規則転移; 熱容量; カルコゲナイド混合導電体

In a family of layered chalcogenide compounds of type MCrX_2(M=Ag, Cu, Li, Na, K; X=S, Se), CrX_2 forms sandwich-layers of trigonal symmetry, between which the monovalent cations are intercalated. The cations Ag, Cu are located on the tetrahedrally coordinated sites which form puckered honeycomb lattices. In the case of M=Li, Na and K, the cations are located on the octahedrally coordinated sites which from trigonal lattices. The purpose of this research is to clarify the relationship between of the structure and the ion conduction mechanism, and the other properties of the compounds.High-purity samples of AgCrS_2 and CuCrS_2 were synthesized directly from the elements in a fused-silica tube at 1270 K. The measurements were carried out for high temperature electric conductivity and heat capacity by adiabatic calorimetry from 7 to 327 K and by ac calorimetry from room temperature up to 720 K. An order-disorder phase transition has been observed at 673 K in AgCrS_2 and 691 K in CuCrS_2. … More The heat capacity anomaly is of a typical second-order transition associated with little fluctuation in the order parameters at the transition points. The mechanism of the transition has been discussed in terms of the critical exponents. The value of the defect formation enthalpy in AgCrS_2 were determined from the excess heat capacities below the transition temperature. The antiferromagnetic-paramagnetic phase transition has been detected as a diffused first-order type of anomaly at 42.02 K in AgCrS_2 and 37.42 K in CuCrS_2. The value of transition entropy indicates that the ordering of the magnetic spins is well established through the phase transition. The phase diagram of Ag_xCu_<1-x>CrS_2 system has been studied by DTA and powder X-ray diffraction. High-purity samples of NaCrS_2 were also synthesized with Na_2-S flux and characterized by using X-ray diffraction and DTA. Heat capacity measurements were made between 7 to 300 K, and the results have been analyzed and discussed in detail. Less

在MCRX_2型的分层葡萄染色质化合物（M = Ag，Cu，Li，Na，K; X = S，SE）中，CRX_2形成三角形对称性的三明治层，在其中将单价阳离子插入。阳离子AG，Cu位于四面体配位的位置，形成了冰ish蜂窝状的晶格。在M = Li，Na和K的情况下，阳离子位于三角形晶格的八面体配位地点。 The purpose of this research is to clarify the relationship between the structure and the ion conduction mechanism, and the other properties of the compounds.High-purity samples of AgCrS_2 and CuCrS_2 were synthesized directly from the elements in a fused-silica tube at 1270 K. The measurements were carried out for high temperature electric conductivity and heat capacity by adiabatic calorimetry from 7 to 327 K and by ac从室温到720 K的量热法。在CUCRS_2中，在AGCRS_2和691 K中观察到订单disorder相变。 …更多的热容量异常是典型的二阶转变，与过渡点处的顺序参数相关的波动很少。已经根据关键指数讨论了过渡的机制。从过渡温度以下的过量热容量确定AgCRS_2中缺陷形成焓的值。在CUCRS_2中，在AGCRS_2和37.42 K中检测到抗磁性 - 磁相变为42.02 K的散射的一阶异常。过渡熵的值表明，通过相变很好地确定了磁旋的顺序。 AG_XCU_ <1-X> CRS_2系统的相图已通过DTA和粉末X射线衍射研究。 NACRS_2的高纯度样品还与Na_2-S通量合成，并通过使用X射线衍射和DTA进行表征。进行了7至300 K之间的热容量测量，并详细分析了结果和讨论。较少的

项目成果

Tooru ATAKE: "Low Temperature Heat Capacities of NaCrS_2"

Toru ATAKE：“NaCrS_2 的低温热容”

Tooru ATAKE: "AC Calorimetric Studies of the Phase Transition at 673 K in AgCrS_2" Proceedings of the 172nd Meeting of the Electrochemical Society. (1988)

Tooru ATAKE：“AgCrS_2 中 673 K 相变的交流量热研究”电化学会第 172 届会议论文集。

Hitoshi,KAWAJI: J. Phys. Chem. Solids. (1989)

川地仁：《物理学杂志》。

Hitoshi KAWAJI: J.Phys.Chem.Solids. 50. 215-220 (1989)

川地仁：《物理化学固体杂志》。

Tooru ATAKA: Proceedings of the 172nd Meeting of the Electrochemical Society. (1988)

Tooru ATAKA：电化学学会第 172 届会议记录。