Synthesis of transition metal oxides under extremely high oxygen pressure

极高氧压下合成过渡金属氧化物

• 批准号: 11554015
• 负责人: TAKAHASHI Hiroki
• 金额: $ 9.02万
• 依托单位: Nihon University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11554015/
• 关键词: high-pressure synthesis; high-T_c superconductor; diamond anvil; nitride; laser heating; excess oxygen; 高温超伝導体; 高圧; 高酸素圧; レーザー可熱; 遷移金属酸化物; ダイヤモンドアンビルセル; 高温超伝導

Recently great attention has been paid for high-pressure research. The advantage of high-pressure research is to make continuous change of sample volume without introducing randomness effect which is often caused by alloying and/or atom substitution. On the other hand high-pressure technique is well applied for material synthesis.In this project, we have built a high-pressure experiment system using a diamond anvil cell (DAC) which can generate very high pressure more than 10 GPa.. In this system, the material is sealed in the DAC with oxygen and can be heated by YAG laser. Diamond is transparent for infrared laser and it is designed that the laser beam can heat the material in the DAC in both direction. This laser heating method is usually used in the earth science in which interior materials have been synthesized. It is first time to use laser heating method in DAC for superconducting materials.The measurement system for synthesized sample has also built in this project. In order to … More measure the magnetic properties, AC susceptibility measurement system has been built. Special care is taken for detecting very small signal from the sample which placed in the very small high-pressure space. Our target pressure range is 10 GPa to 100 GPa. Using this system we studied superconducting transition, insulator-metal transition, and magnetic transition. Novel quantum transitions are expected to be discovered. The DAC are made from non-magnetic CuBe alloy and driven by pneumatic system to keep constant pressure at low temperature.In this work the laser heating under extremely high oxygen pressure has been carried out for La_2CuO_4 and YBa_2Cu_3O_7. The superconducting trnsition temperature(TC) of La_2CuO_4 is known to be sensitive to the excess oxygen accommodated in the material and T_c of YBa_2Cu_3O_7 is also sensitive to the oxygen defect. Thus these materials are good sample for testing our experiment system. Synthesis of nitride using DAC under high nitrogen pressure has also been tried for NbN.Since it is difficult to detect the superconductivity in DAC because of the amount of specimen is extremely small, SQUID magnetometer is also used with DAC. Special DAC was designed for SQUID.Discovery of new superconducting materials is expected in the high-pressure reserch. Less

近年来，高压研究引起了人们极大的关注。高压研究的优点是使样品体积连续变化，而不会引入通常由合金化和/或原子替代引起的随机效应。另一方面，高压技术在材料合成中有着广泛的应用，本课题利用金刚石对顶砧（DAC）建立了一套高压实验系统，可以产生10 GPa以上的超高压。在该系统中，材料被密封在DAC中与氧气，并可以通过YAG激光器加热。金刚石对红外激光是透明的，并且其设计使得激光束可以在两个方向上加热DAC中的材料。这种激光加热方法通常用于合成内部材料的地球科学。首次将激光加热方法应用于超导材料的DAC中，并建立了合成样品的测量系统。为了 ...更多信息 磁性能测量，建立了交流磁化率测量系统。特别注意从放置在非常小的高压空间中的样品中检测非常小的信号。我们的目标压力范围是10 GPa到100 GPa。利用这个系统，我们研究了超导转变、绝缘体-金属转变和磁转变。新的量子跃迁有望被发现。DAC由非磁性CuBe合金制成，由气动系统驱动，在低温下保持恒压，本文对La_2CuO_4和YBa_2Cu_3O_7进行了超高氧压下的激光加热。La_2CuO_4的超导转变温度（TC）对氧缺陷敏感，YBa_2Cu_3O_7的T_c对氧缺陷敏感。因此，这些材料是测试我们的实验系统的好样本。对于NbN，也尝试了在高氮气压力下使用DAC合成氮化物。由于样品量极小，难以检测DAC中的超导性，因此SQUID磁强计也与DAC一起使用。为SQUID设计了专用DAC，有望在高压研究中发现新的超导材料。少

项目成果

T.Nakanishi, N.Motoyama, H.Mitamura, N.Takeshita, H.Takahashi, H.Eisaki, S.Uchida, T.Goto, H.Ishimo**, N. Mori: "Pressure and field dependence in the spin-ladder Sr_<14-x>Ca_xCu_<24>0_<41>"J. Magn. Magn. Mat.. 226-230. 449-451 (2001)

T.Nakanishi、N.Motoyama、H.Mitamura、N.Takeshita、H.Takahashi、H.Eisaki、S.Uchida、T.Goto、H.Ishimo**、N. Mori：“旋转中的压力和场依赖性

辺土正人: "Pressure-induced structural phase transition of CeRu_2."Physica. 218&282. 88-89 (2000)

Masato Hedo：“CeRu_2 的压力诱导结构相变”，Physica 218&282 (2000)。

T.Nakanishi: "Pressure and field dependence in the spin-ladder Sr_<14>-xCaxCu_<24>O_4 1"Journal of Magnetism and Magnetic Materials. 226-230. 449-451 (2001)

T.Nakanishi：“自旋梯 Sr_<14>-xCaxCu_<24>O_4 1 中的压力和场依赖性”《磁性与磁性材料杂志》。

中西 剛司: "Pressure and field dependence in the spin-ladder Sr_<14-x>CaxCu_<24>O_<41>"J.Magn.Magn.Mat. 226-230. 449-451 (2001)

Takeshi Nakanishi：“自旋梯 Sr_<14-x>CaxCu_<24>O_<41> 中的压力和场依赖性”J.Magn.Magn.Mat 226-230 (2001)。

H.Kobayashi: "Pressure-induced semiconductor-metal-semiconductor transitions in FeS"Physical Review B. 63. 115203 (2001)

H.Kobayashi：“FeS 中压力诱导的半导体-金属-半导体转变”物理评论 B. 63. 115203 (2001)