Precise study of pressure-induced quantum phase transitions under very high pressure

极高压力下压力引起的量子相变的精确研究

基本信息

批准号：
15204032
负责人：
SHIMIZU Katsuya
金额：
$ 32.12万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2006
项目状态：
已结题

项目摘要

By combination of very-high-pressure generating technology and ultra-fine processing technology, we have studied physical properties of materials. Especially for the purpose of clarify the mechanism of the quantum phase transition phenomena (superconductive transition, magnetic phase transition, insulator-to-metal transition, etc.) which have attracted many physicists recent years. Here we summarize our achievements on the technical developments and the physical results of the research shown as below:1.Electrical resistance measurements: Creation of a fine electrical probes with an interval of 5 microns was succeeded by using lithography and lift-off process. Measurement under very high pressure over 1,500,000 atmospheres were carried out by this technique. One of highlights is detection of high-temperature superconductivity of calcium of exceeding 25 K which is the highest value among the elements.2.Magnetization measurements: As a result of improving the precision magnetization measu … More ring device in DAC using a SQUID magnetometer with oscillating-coil technique (VCM), the good S/N (signal to noise) ratio can be obtained.3.AC calorimetry measurements: By adding the electrical proves for the specific heat measurements to electrical resistance measurement proves, coincidence measurement of specific heat measurement and electrical resistance measurement became possible under high pressure of 10 GPa. This technique revealed the mechanism of metal-to-insulator transition of one of Skutterdite compound of PrRu4Pi2under high pressure.4.Thermal expansion measurements: Attachment of a small strain gauge to the sample of 100-micron length became possible using the lithography technique. It became clear that the antiferromagnetic transition can be detected with sufficient sensitivity.5.Structural analysis: In situ synchrotron structural analysis with electrical resistance measurements became possible under very high-pressure and low-temperature conditions. We have succeeded to detect the superconductive transition temperature of lithium and crystal structural changes up to about 1 million atmosphere pressure. Less

通过结合超高压发生技术和超精细加工技术，我们研究了材料的物理性质，特别是为了阐明量子相变现象（超导相变、磁相变、绝缘体相变）的机理。 -金属过渡等），我们将近年来吸引众多物理学家的技术发展和物理研究成果总结如下： 1.电阻测量：创建具有间隔的精细电探针。共 5 个通过使用光刻和剥离工艺，在超过 1,500,000 个大气压的超高压下实现了微米级测量，其亮点之一是检测到了超过 25 K 的高温超导性，这是目前为止最高的值。 2.磁化测量：由于使用采用振荡线圈技术的 SQUID 磁力计改进了 DAC 中环形装置的精确磁化测量（VCM），可以获得良好的S/N（信噪比）。3.交流量热测量：通过将比热测量的电学证明添加到电阻测量证明中，比热测量和电阻的一致性测量在 10 GPa 的高压下进行测量成为可能。该技术揭示了 PrRu4Pi2 的一种方钴矿化合物在高压下的金属到绝缘体转变的机制。4.热膨胀测量：将小型应变计连接到使用光刻技术可以实现 100 微米长度的样品。很明显，可以以足够的灵敏度检测反铁磁转变。5.结构分析：在非常高的压力和电阻下进行原位同步加速器结构分析成为可能。我们已经成功地检测到了约100万个大气压以下的锂的超导转变温度和晶体结构的变化。