高圧力の科学と技術
Online ISSN : 1348-1940
Print ISSN : 0917-639X
ISSN-L : 0917-639X
最新号
選択された号の論文の12件中1~12を表示しています
巻頭言
特集:高圧メルトの実験最前線
受賞記念解説:高圧力学会学会賞
受賞記念解説:高圧力学会奨励賞
  • 若林 大佑
    2019 年 29 巻 2 号 p. 129-137
    発行日: 2019年
    公開日: 2019/07/18
    ジャーナル フリー

    The permanent densification of SiO2 glass has long attracted considerable attention in various fields such as condensed-matter physics, materials science, and geophysics. We have conducted isotropic- and uniaxial-compression experiments and ab-initio molecular-dynamics simulations to understand the permanent densification. It has been clarified that the permanent densification can be interpreted as a phase transition in the intermediate-range order (the network structure of SiO4 tetrahedra) and it changes not only density but also plasticity. This article attempts to review the permanent densification of SiO2 glass and introduce an application to estimate the behavior of magma in the Earth's deep upper mantle, based on our recent researches.

  • 青山 拓也
    2019 年 29 巻 2 号 p. 138-143
    発行日: 2019年
    公開日: 2019/07/18
    ジャーナル フリー

    The hydrostatic pressure effect on multiferroic properties of rare-earth manganites RMnO3 (R=Dy, Tb, and Gd) with the Pbnm orthorhombic structure was investigated by using a diamond anvil cell. Under high pressures, all of these manganites were found to exhibit ferroelectricity in which spontaneous polarization (≈100 µC cm-2) develops along the a axis. The application of a magnetic field B along the a axis to the high-pressure ferroelectric phase causes a drastic change in the electric polarization P. Especially in GdMnO3, the B-induced change in P reached ΔP(B)=1.3 µC cm-2. A possible origin of the observed R-dependent pressure effect is discussed.

解説
  • 米田 明, 小林 真一郎, 鎌田 誠司
    2019 年 29 巻 2 号 p. 144-155
    発行日: 2019年
    公開日: 2019/07/18
    ジャーナル フリー

    GHz ultrasonic velocity measurement has been developed up to ~15 GPa in a diamond anvil cell (DAC). In order to perform the GHz ultrasonic measurement, both P and S wave buffer rods were manufactured through sputtering ZnO piezoelectric film on single crystal rods, such as sapphire, rutile (TiO2), and YAG. Several technical breakthroughs have been achieved before observing stable signals from the specimen squeezed in DAC: (1) Wiping by aqueous ammonia on the contact surfaces enhances transmissibility of GHz waves from the buffer rod to the diamond anvil. (2) Cleaning with lathery detergent and water jet effectively removes grime on the rear surface of the diamond. (3) A steel ball supporter allows effortless adjustment of contact between the buffer rod and the diamond. As a result, we succeeded in demonstrating the GHz-DAC ultrasonic velocity measurement on KCl and natural olivine samples.

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