Search for the thermodynamic anomaly at extremely low temperatures in the carrier-doped organic superconductors using a microchip calorimeter

使用微芯片热量计寻找载流子掺杂有机超导体中极低温下的热力学异常

• 批准号: 15340116
• 负责人: NAKAZAWA Yasuhiro
• 金额: $ 9.54万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15340116/
• 关键词: heat capacity; superconductivity; electronic heat capacity coefficient; incommensurate; インコメンシュレート; マイクロチップカロリーメーター; ホールドープ; 電子状態

In this project, we aim at designing calorimeter for measuring heat capacities of small single crystals of organic superconductors. In the former half of the research period, we constructed calorimeter available under magnetic fields up to 15T, and then we measured the samples of organic salts of which donor and anion ratio is non-stoichiometric.At first, we studied (MDT-TSF)(AuI_2)_<0.436> (T_c=4.3K) and observed a broad maximum at about 3.8K. Although the peak itself is broadened, the magnetic field dependence was observed up to 6T which is consistent with the magnetic and transport behaviors. Since the incommensurate relation between donor layers and anion layers, the electrons in the donor layers feels a kind of random potential and intrinsic peak-broadening effect seems to be occurring in this salt. The heat capacity of κ-(BEDT-TTF)_4Hg_<2.89>Br_8 is also studied. In addition to the incommensurate effect appears as a peak-broadening of the superconductive transitions, we have observed that the electronic heat capacity coefficient is enhanced up to the 50 mJK^<-2>mol^<-1>. The drastic cooling rate dependence of heat capacity anomalies around the superconductive transition temperature is also observed.The technique developed through this project is available to the other molecular materials which usually yielded as a small pieces of crystals.

本项目旨在设计一种用于测量有机超导体小单晶热容的量热计。在前半部分的研究中，我们构建了可在高达15 T的磁场下使用的量热计，然后测量了给体与阴离子比为非化学计量比的有机盐样品，首先研究了（MDT-TSF）（AuI_2）_<0.436>（T_c=4.3K），在3.8K左右观察到一个宽的最大值。虽然峰本身被加宽，但观察到高达6 T的磁场依赖性，这与磁性和输运行为一致。由于施主层和阴离子层之间的不相称关系，施主层中的电子感受到一种随机势，在这种盐中似乎发生了本征峰展宽效应。本文还研究了κ-（BEDT-TTF）_4Hg_Br_8的热容<2.89>。除了无公度效应表现为峰加宽的电子跃迁外，我们还观察到电子热容系数提高到50 mJ·K·<-2>mol·L-1<-1>。通过该项目开发的技术也适用于其他通常以小块晶体形式产出的分子材料。

项目成果

Low-Temperature Heat Capacity of the Mn(III)-porphyrin-TCNE ferrimagnetic complexes,[MnTXPP][TCNE]・2PhMe,(X=Cl,Br)

Mn(III)-卟啉-TCNE 亚铁磁配合物[MnTXPP][TCNE]·2PhMe,(X=Cl,Br)的低温热容

• 发表时间: 2005
• 期刊: Solid State Commun. 135
• 作者: Y.Nakazawa;W.Horrman;J.S.Miller;M.Sorai
• 通讯作者: M.Sorai

Novel Superconductivity Coexisting with Incipient Electron-Multipolar Order in CePtSi

CePtSi 中新型超导性与初始电子多极有序共存

• 发表时间: 2005
• 期刊: J. Phys. : Condensed Matter 17
• 作者: M.Ishikawa;S.Yamashita;Y.Nakazawa;N.Takeda;N.Wada
• 通讯作者: N.Wada

Drastic Cooling Rate Dependence of Thermal Anomaly Associated with the Superconducting Transition in κ-(BEDT-TTF)_4Hg_<289>Br_8

κ-(BEDT-TTF)_4Hg_<289>Br_8 中与超导转变相关的热异常的剧烈冷却速率依赖性

• 发表时间: 2005
• 期刊: Journal of Calorimetry and Thermal Analysis (in press)
• 作者: S.Yamashita;A.Naito;Y.Nakazawa;K.Saito;H.Taniguchi;K.Konoda;M.Oguni
• 通讯作者: M.Oguni

第5版 実験化学講座7 電気物性 磁気物性 11.3,13.1担当

第五版实验化学课程7电性质磁性质11.3,13.1负责

• 发表时间: 2004
• 作者: 大竹雄次;新谷昌人;渡辺好徳;肥田野和夫;日本化学会編(中澤康浩)
• 通讯作者: 日本化学会編(中澤康浩)

Y.Nakazawa, A.Sato, M.Seki, K.Saito, K.Hiraki, T.Takahashi, K.Kanoda M.Sorai: "Spin-Peierls Transition of Quasi-One-Dimensional Electronic System (DMe-DCNQI)_2M(M=Li, Ag) Probed by Heat Capacity"Physical Review B. 68. 085112-1-085112-8 (2003)

Y.Nakazawa、A.Sato、M.Seki、K.Saito、K.Hiraki、T.Takahashi、K.Kanoda M.Sorai：“准一维电子系统的自旋-佩尔尔斯转变（DMe-DCNQI）_2M