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Yagafarov, O.; Katayama, Yoshinori; Brazhkin, V. V.*; Lyapin, A. G.*; Saito, Hiroyuki
High Pressure Research, 33(1), p.191 - 195, 2013/01
Times Cited Count：5 Percentile：37.63(Physics, Multidisciplinary)Yagafarov, O.; Katayama, Yoshinori; Brazhkin, V. V.*; Lyapin, A. G.*; Saito, Hiroyuki
Physical Review B, 86(17), p.174103_1 - 174103_9, 2012/11
Times Cited Count：30 Percentile：73.03(Materials Science, Multidisciplinary)
O
glassBrazhkin, V. V.*; Akola, J.*; Katayama, Yoshinori; Kohara, Shinji*; Kondrin, M. V.*; Lyapin, A. G.*; Lyapin, S. G.*; Tricot, G.*; Yagafarov, O.
Journal of Materials Chemistry, 21(28), p.10442 - 10447, 2011/07
Times Cited Count：19 Percentile：48.01(Chemistry, Physical)PO compound is an archetypical glass-forming oxide with a high hygroscopicity. We found that the quenching from the POmelt under ultrahigh pressures enables obtaining densified PO glasses with a residual densification up to 12% at normal conditions. These glasses have a low hygroscopicity and can exist under air conditions for several weeks. An examination of the structure of the new form of PO glass reveals a cardinal decrease of the volume of nanovoids in the glassy matrix.
Hattori, Takanori; Sano, Asami; Inamura, Yasuhiro; Funakoshi, Kenichi*; Abe, Jun*; Machida, Shinichi*; Okazaki, Nobuo*; Katayama, Yoshinori; Yagafarov, O.*; Chiba, Ayano*
no journal, ,
SiO glass consists of SiO
tetrahedra. This glass is easily densified by applying pressure, due to its relatively sparse network ring formed by the linkage of tetrhaera. The density increase amounts to 20% by room temperature compression to 8 GPa. This increase is, however, released after decompression because of insufficient structural relaxation. On the other hand, the heating at high pressures promotes the structural relaxation, resulting in permanent densification of 20% at most. The mechanism of this densification has been investigated so far, but the microscopic origin is still to be revealed. So, we performed in-situ high-pressure neutron experiments at newly constructed high-pressure neutron beamline PLANET in J-PARC. We will discuss the origin of the reversibility in the densification.
under high pressureMachida, Akihiko; Watanuki, Tetsu; Hattori, Takanori; Sano, Asami; Yagafarov, O.*; Katayama, Yoshinori; Aoki, Katsutoshi; Oshita, Hidetoshi*; Ikeda, Kazutaka*; Otomo, Toshiya*
no journal, ,
no abstracts in English
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Matsuzaki, Yuki*; Shimojo, Fuyuki*
no journal, ,
We recently constructed the diffractometer dedicated to high-pressure purpose at pulsed neutron source J-PARC. This beamline has the huge 6-axis multi-anvil press, which is good at generating high-pressure and high-temperature condition simultaneously. By developing devices to eliminate scattering from materials around the sample, such as a sample container, a heater, we can obtain very clear pattern even under high-PT condition. This enables us to analyze the PT dependence of the structure of amorphous solids and liquids with high quality. I will explain the performance of the beamline and the PT modification of SiO
glass.
Katayama, Yoshinori; Yagafarov, O.; Ikeda, Takashi; Saito, Hiroyuki; Aoki, Katsutoshi; Hattori, Takanori; Fukui, Hiroshi*; Tange, Yoshinori*; Funakoshi, Kenichi*
no journal, ,
Liquid water at ambient pressure shows unique properties and they are related to the network structure formed by hydrogen bonds between water molecules. To study structural change in the liquid water under high-pressure and high-temperature conditions, we have measured X-ray diffraction of liquid water just above the melting line up to 20 GPa. Up to 4 GPa, the coordination number increased rapidly while the intermolecular distance changed slightly. First-principles molecular dynamics simulations were also performed for high-density water. Results of the simulations in a wide pressure- temperature range revealed that temperature was more important factor for the crossover between the hydrogen-bonded and simple liquid-like liquids. We have measured X-ray diffraction of water as a function of temperature. The experimental results supported the results of the simulation.
Yagafarov, O.; Katayama, Yoshinori; Brazhkin, V. V.*; Lyapin, A. G.*; Saito, Hiroyuki
no journal, ,
Yagafarov, O.; Katayama, Yoshinori; Brazhkin, V. V.*; Lyapin, A. G.*; Saito, Hiroyuki
no journal, ,
Gallium has a unique crystal structure which has Ga as building blocks. Many phases are found as function of temperature and pressure. The structure of liquid cannot be described as a simple hard-sphere model. In this study, details of structural changes of liquid under high-pressure and high-temperature conditions were investigated using modern measurement and analysis methods, reliable density data, a quasi-crystalline model and a reverse Monte Carlo method. The energy-dispersive X-ray diffraction measurements along the melting curve up to 5.3 GPa were carried using a cubic-type multi-anvil press installed on a JAEA beamline, BL14B1, in SPring-8. Structural change towards a simple-liquid like structure was observed.
Katayama, Yoshinori; Hattori, Takanori; Saito, Hiroyuki; Sano, Asami; Suzuya, Kentaro; Yagafarov, O.*; Chiba, Ayano*; Otomo, Toshiya*
no journal, ,
Liquid water at ambient conditions has an ice-like, characteristic structure due to the hydrogen bonds between molecules. To study pressure and temperature dependence of the structure of water, we have carried out in-situ high-temperature high-pressure measurements on liquid water using synchrotron radiation at the SPring-8 and molecular dynamics simulations. The results revealed transformation from the ice-like structure to a simple-liquid-like structure. To investigate change in hydrogen bonds, neutron is an important probe. We carried out neutron diffraction measurements on heavy water at room temperature, 100
C and 200C at 0.8 GPa using newly-built high-pressure diffractometer, PLANET, at J-PARC/MLF. Significant temperature dependence of diffraction pattern was observed.
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*
no journal, ,
SiO glass is an amorphous solid consisting of SiO tetrahedra. Each tetrahedra are connected to each other, and forms the many-menbered ring. Thus, the glass has large void space and therefore marked densification is expected under pressure. Actually, the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original one on room-temperature decompression, but the high-density state is maintained once the sample is heated under pressure by structural relaxation (permanent densification). So far, the mechanism has been investigated, but remains to be revealed. To reveal the mechanism, in situ high-pressure diffraction is indispensable. Such data were obtained up to 10 GPa at the high-pressure neutron diffactometer PLANET in the last year, therefore we developed the method to analyze the data this year. By developing the program, we succeeded in obtaining structure factor and confirmed its reliability by comparing with the previous results.
Katayama, Yoshinori; Hattori, Takanori; Yagafarov, O.*; Saito, Hiroyuki; Sano, Asami; Suzuya, Kentaro; Chiba, Ayano*; Otomo, Toshiya*
no journal, ,
Liquid water at ambient conditions has an ice-like, characteristic structure due to the hydrogen bonds between molecules. To study pressure and temperature dependence of the structure of water, we have carried out in-situ high-temperature high-pressure measurements on liquid water by in-situ synchrtorn X-ray diffraction experiments at the SPring-8 and molecular dynamics simulations. The results revealed transformation from the ice-like structure to a simple-liquid-like structure. To investigate change in hydrogen bonds, neutron is an important probe. We carried out neturon diffraction measurements on heavy water at 100
C and 200C at 2 GPa using high-pressure diffractometer, PLANET, at J-PARC/MLF. Significant temperature dependence of width of first peak in diffraction pattern, which is similar to that observed in the previous neutron diffraction experiments at 0.8 GPa.
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Matsuzaki, Yuki*; Shimojo, Fuyuki*
no journal, ,
PLANET is the beamline dedicated for the high-pressure experiments. The operation has been started at JFY 2013, and now many users are coming to use. In this talk, we introduce the current state of the PLANET and the example of the structure analysis of disordered materials. PLANET adopted the double staged compression system of the multi anvil 6-6, and enables the data collation at 10 GPa and 2000 K. To extend accessible PT range, we newly introduce another compression system of multi-anvil 6-8, and succeeded in generating 16 GPa and 1273 K. In addition, the PLANET is designed so that we can analyze the structure of liquid under pressure. In the analysis, the program for liquid analysis developed at BL21 NOVA is used. Here, we briefly introduce the reliability of the results and the pressure evolution of the silica glass.
glass at high pressures and high temperaturesHattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Sano, Asami; Inamura, Yasuhiro
no journal, ,
PLANET is the powder neutron diffractometer constructed at MLF in J-PARC, which specialize in high-pressure experiments. The most characteristic feature of the beamline is its capability to analyze the structure of materials under high-pressure and temperature of 10 GPa and 2000 K. This beamlines is equipped with several collimation devices to remove parasitic scattering from sample surrounding materials. In this study, we carried out in-situ neutron diffraction experiments on silica glass to reveal the mechanism of permanent densification. In S(Q), no significant change was observed in the oscillation over wide Q-range, but marked changes were observed in the low Q region. The coordination number remained 4 up to 17 GPa. These features are consistent with previously known mechanism: glass is densified by changing intermediate range rather than by changing short range order. In the poster, we will introduce structural changes under high-pressure and high-temperature conditions.
glass at high-PT condition by in-situ neutron diffractionHattori, Takanori; Sano, Asami; Inamura, Yasuhiro; Yagafarov, O.*; Katayama, Yoshinori*; Chiba, Ayano*; Otomo, Toshiya*; Funakoshi, Kenichi*; Abe, Jun*; Machida, Shinichi*; et al.
no journal, ,
SiO glass consists of SiO
tetrahedra which are mutually connected and forms the many-membered ring. Thus, the glass has large void in its structure, and therefore marked densification is expected under pressure. Actually, it is known that the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original value by decompression, whereas the high-density state is retained at ambient condition once the structure is relaxed by being heated at high pressures. In this study, the mechanism of the densification at room-temperature and high-temperature has been investigated by in-situ high-pressure neutron diffraction at high-pressure neutron beamline PLANET in J-PARC. Then, we have constructed 3-dimensional atomic arrangements by Reverse Monte Carlo simulation, coupling with previously reported X-ray data. In this talk, the mechanism of densification at room-temperature and high-temperature and their differences will be discussed based on the obtained atomic arrangements.
glass at high-PT condition by in-situ X-ray and neutron diffractionHattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori*; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Machida, Shinichi*; Abe, Jun*; Funakoshi, Kenichi*; et al.
no journal, ,
SiO glass consists of SiO tetrahedra which are mutually connected and forms the many-membered ring. Thus, the glass has large void in its structure, and therefore marked densification is expected under pressure. Actually, it is known that the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original value by decompression, whereas the high-density state is retained at ambient condition once the structure is relaxed by being heated at high pressures. In this study, the mechanism of the densification at room-temperature and high-temperature has been investigated by in-situ high-pressure neutron diffraction at high-pressure neutron beamline PLANET in J-PARC. Then, we have constructed 3-dimensional atomic arrangements by Reverse Monte Carlo simulation, coupling with previously reported X-ray data. In this talk, the mechanism of densification at room-temperature and high-temperature and their differences will be discussed based on the obtained atomic arrangements.
Katayama, Yoshinori; Yagafarov, O.; Hattori, Takanori; Suzuya, Kentaro; Inamura, Yasuhiro; Chiba, Ayano*; Otomo, Toshiya*; Temleitner, L.*; Kohara, Shinji*
no journal, ,
The purpose of our project is structural analysis of liquid water and other structurally disordered materials under high pressure using a high-pressure neutron beamline which is under construction in J-PARC/MLF. In this presentation, we will review recent studies toward the neutron experiments, such as synchrotron radiation X-ray diffraction studies on liquid water under high-pressure and high-temperature conditions, and Reverse Monte Carlo modeling of permanently densified silica glass using both X-ray and neutron data.
glass study by RMC simulation using X-ray and neutron diffraction dataYagafarov, O.; Kohara, Shinji*; Temleitner, L.*; Inamura, Yasuhiro; Katayama, Yoshinori
no journal, ,
Yagafarov, O.; Katayama, Yoshinori; Brazhkin, V. V.*; Lyapin, A. G.*; Saito, Hiroyuki
no journal, ,
Katayama, Yoshinori; Yagafarov, O.; Machida, Akihiko; Hattori, Takanori; Sano, Asami; Komatsu, Kazuki*; Otomo, Toshiya*
no journal, ,
To test feasibility of neutron diffraction measurements of glass at high pressures up to several GPa, a sample of silica glass in a Paris-Edinburgh type high-pressure apparatus was measured at ambient conditions using a total scattering spectrometer, NOVA, at the Japan Proton Accelerator Complex (J-PARC). The sample has a shape of double convex lens, 6 mm in diameter, 4.4 mm in thickness. It was surrounded by a ring-shape gasket made of TiZr alloy and two anviles made of tungsten carbide. The incident neutron beam passed through a anvil and the diffracted beam passed through the gasket. The data acquisition time was about 20 hours. A vanadium sample and the empty gasket were also measured as references. A clear oscillation was observed in the intensity as a function of wave number.
