Preparation and Properties of Layer Structured High-Tc Superconductors

层状结构高温超导体的制备及性能

• 批准号: 12450353
• 负责人: YAMANAKA Shoji
• 金额: $ 10.37万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450353/
• 关键词: Superconductor; Layer structured nitrides; Single crystal growth; High pressure synthesis; Anisotropic superconductivity; Nitride thin films; 高温超伝導; インターカレーション; 電子ドープ; NMR; 単結晶

1. The layer structured nitride chlorides, β-MNCl (M = Zr, Hf) can be electron-doped by the intercalation of lithium, and are changed into superconductors with the superconducting transition temperatures (Tc's) of 14 and 25.5 K for M = Zr and Hf, respectively. The interlayer spacing can be controlled by the co-intercalation of polar solvent molecules with lithium ions, and the anisotropy of the superconductivity is greatly enhanced. The NMR and muon spin relation measurements revealed that the electron-doped layer structured nitride superconductors have the following characteristics ; (i) highly anisotropic exotic superconductors, (ii) low carrier density near Fermi level, 〜10^<21>/cm^3, (iii) very small isotope effect on the replacement with ^<15>N, and (iv) low phonon excitation. The superconductivity is very unconventional.2. The layer structured nitride chlorides, β-MNCl (M = Zr, Hf) were so thin and so soft crystals that it was very difficult to use for X-ray structural analysis a … More nd physical property measurements. We have succeeded to develop a new high pressure synthesis method to obtain thick single crystals using ammonium chloride as flux. All kinds of β-MNX (M = Zr, Hf ; X = Cl, Br, I) were also obtained as single crystals, and the crystal structures were determined by X-ray single crystal analyses. It was found that the compounds were crystallized into the two different polytypes, the SmSI and the YOF structures.3. In an attempt to tailor new layer structured nitride compounds, thin artificial nitride films were prepared using electron-beam evaporation and lazer ablation methods with a nitrogen radical source under ultrahigh vacuum conditions. Titanium nitride, TiN, films were epitaxially grown on MgO (100) substrates, and the layer-by-layer growth was successfully monitored by RHEED. CrN could be epitaxially deposited on Si(100), and an expitaxial NbN film was subsequently grown on the CrN film. This finding suggests the possibility of the synthesis of artificial CrN-NbN films with superstructures. Less

1。层结构化氮化物氯化物，β-MNCL（M = ZR，HF）可以通过锂S与超导导向过渡温度（TC）的插入14和25.5 k的插入，用于m = Zr和Hf，M = Zr和HF，层间间距可以通过超导性的锂离子的共同溶剂分子得到大大增强^3，（iii）非常小的同位素对^<15> n的替换，（iv）低电话传导性非常规。2 X射线结构分析很难使用的软晶体。 MNX（M = Zr，HF; X = Cl，Br，I）也作为单晶体获得，并通过X射线单晶体分析确定晶体结构。 YOF结构。3尝试量身定制硝酸盐化合物，使用具有氮基源的蒸发剂evazer ab tinries，在超高真空状态下制备了硝酸盐薄膜。层的生长成功地在CRN膜上生长