Development of superconductors with porous structures

多孔结构超导体的开发

基本信息

批准号：
16205027
负责人：
YAMANAKA Shoji
金额：
$ 30.7万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

i. Construction of the high-pressure synthesis apparatusThe high-pressure synthesis apparatus of the cubic multianvil type has been changed to the 6-8 Kawai type anvil to enable a higher pressure condition up to 20 GPa at 2000 °C.ii. Development of new superconductors with silicon nano-networksThe silicon clathrate superconductor Ba_8Si_<46> previously found in our group,.was transformed into the silicon rich compound BaSi_6 under extremely high pressure conditions. A new silicon rich phase LaSi_5 in the La-Si binary system has been prepared under a high pressure of 15 GPa, which became a superconductor with Tc = 11 K.iii. High pressure synthesis of carbon clathrate compoundIn the course of the study to prepare carbon clathrate compounds, two different types of crystalline three-dimensional C_<60> polymers have been prepared, body centered orthorhombic and face centered cubic 3D polymers. Their structural analyses, electrical conductivity measurements, and micro-Vickers measurements were carried out.iv. Development of new layer structured nitride superconductorsZr_5N_5F_6 and Hf_5N_5F_6 were prepared, and their single crystals were grown using a high-pressure flux method. The structural analysis revealed that the compounds had a long periodic structure based on the LaOF type layer structure. The true chemical composition was found to be close to Zr_5(N_40)F_6. The interlayer fluorine atoms could be partially removed, and the layer compound was changed to a new superconductor with Tc=4.5 K.v. Synthesis of thin films of nitride superconductorsMolybdenum nitride thin films were obtained using PLD and MBE deposition with nitrogen RF radical source. B-Mo2N were successfully deposited as thin films, which showed superconductivity of Tc = 5.2 K.

i.高压合成装置的构造将立方多砧型高压合成装置改为6-8 Kawai型砧，以实现在2000℃下高达20 GPa的高压条件。具有硅纳米网络的新型超导体我们课题组先前发现的硅笼形超导体Ba_8Si_<46>，在极高的压力下转化为富硅化合物BaSi_6在15 GPa高压条件下制备了La-Si二元体系中的新型富硅相LaSi_5，该相成为Tc = 11 K的超导体。为了制备碳笼形化合物，制备了两种不同类型的结晶三维C_<60>聚合物，体心斜方和面心立方3D聚合物，它们的结构分析， iv.制备了新型层状结构氮化物超导体Zr_5N_5F_6和Hf_5N_5F_6，并采用高压通量法生长了它们的单晶。发现基于LaOF型层状结构的长周期结构与Zr_5(N_40)F_6接近。部分去除层间氟原子，将层状化合物转变为Tc=4.5 K.v的新型超导体。氮化物超导体薄膜的合成采用B-Mo2N氮源进行PLD和MBE沉积，得到氮化钼薄膜。成功沉积为薄膜，显示出 Tc = 5.2 K 的超导性。