高圧力の科学と技術 Vol. 26(2016) No. 3

巻頭言

科学の秋

亀卦川卓美

公開日: 2016年09月21日

p.213-214

本文PDF[223K]

特集：マルチアンビル型高圧装置を用いた新物質探索

In this article, recent advances in the fundamental and applied high-pressure synthesis of rare-earth borides, especially RB₁₂, were reviewed. High-pressure equipment using the Walker module has been first introduced to Ibaraki University. It seems very convenient for primary users of high-pressure synthesis to use the equipment. We expect novel materials which have exotic physical properties.

水素貯蔵材料開発の為の高圧合成法による新規合金・水素化物の探索

亀川厚則

公開日: 2016年09月21日

p.225-231

Hydrogen storage technique is one of the key technologies to create hydrogen energy society. In this article, high-pressure synthesis of novel alloys and hydrides for hydrogen media was reviewed. New intermetallic compounds and hydrides were synthesized by using multi-cubic anvil system. For example, new MgNi intermetallic compound with a CuTi type structure was synthesized at 6 GPa and 300℃. This compound was stable in ambient pressure and hydrogenated/dehydrogenated reversibly.

キュービックアンビル型高圧装置を活用した新超伝導体探索

伊豫彰

公開日: 2016年09月21日

p.232-239

We searched for new superconductors using cubic-anvil-type high-pressure apparatus. Samples including valence skip elements such as Bi, Sb were intensively investigated. As a result, we have found new superconductors of LaBi₃ and Ba₂Bi₃ with the superconducting transition temperature (T_c) of 7.3 K and 4.4 K, respectively. We also succeeded in enhancing T_c of Au-Sb alloys and SrBi₃ up to 8.1 K and 9.0 K, respectively, by controlling their chemical compositions. In this article, we explain the properties of the superconductors and the research processes that led to the discovery of the new superconductors.

マルチアンビル装置とMg₂Si熱電材料の高圧合成

森嘉久

公開日: 2016年09月21日

p.240-246

High-pressure X-ray diffraction study by using synchrotron radiation source was carried out to determine the synthetic condition of high-pressure synthesis. We also open our cell assembly of multi anvil apparatus which is readily available for beginners of high-pressure experiment. The synthetic condition of Mg₂Si, which is expected to be inexpensive thermoelectric material, was explored by means of X-ray diffraction study. High-pressure synthesis of Mg₂Si was performed by piston cylinder equipment. Thermoelectric properties of Mg₂Si including Seebeck coefficient and electrical conductivity were measured at room pressure and high temperatures. A simple measurement system we develop enables us to measure the thermoelectric properties of small-sized synthesized sample under pressure.

新しい酸素発生触媒材料の高圧合成

山田幾也, 八木俊介

公開日: 2016年09月21日

p.247-252

Recent advances in novel perovskite oxide catalysts synthesized under high pressure are reviewed. The simple Fe⁴⁺-perovskite oxides CaFeO₃ and SrFeO₃ demonstrate high catalytic activity for oxygen evolution reaction (OER) compared with the isoelectronic compound LaMnO₃. The quadruple Fe⁴⁺-perovskite oxide CaCu₃Fe₄O₁₂ displays a high stability in OER conditions, together with its excellent catalytic activity comparable to or exceeding state-of-the-art OER catalysts. The catalytic activity and stability for CaCu₃Fe₄O₁₂ are attributed to the characteristic crystal structure of the quadruple perovskite.

高圧装置を利用した層状Ni酸化物での超伝導探索

上原政智

公開日: 2016年09月21日

p.253-259

We have studied the antiperovskite superconductors and layered Ni oxide Nd_3.5Sm_0.5Ni₃O₈ which has very similar crystal and electrical structure with high-T_c cuprate. In both systems, the materials are not high-pressure stabilized phases. For synthesis of antiperovskite material, high-pressure apparatus has been used to avoid the evaporation from the starting material with high vapor pressure. For layered Ni oxide, high-pressure apparatus has been utilized to make high density powder compact for the electrical resistivity measurement, because Nd_3.5Sm_0.5Ni₃O₈ can be obtained only with powder form. In this article, the research of layered Ni oxide Nd_3.5Sm_0.5Ni₃O₈ system is introduced.