Article
Geochemistry & Geophysics
Man Xu, Zhicheng Jing, Tony Yu, E. Ercan Alp, Barbara Lavina, James A. Van Orman, Yanbin Wang
Summary: Iron-rich silicate melts have been studied for their elastic properties, specifically sound velocities, at high pressure and temperature conditions. The results show that iron can reduce sound velocity while increasing density of silicate melts. The study also found that although density of the melts can be described by a linear mixing law empirically, sound velocities do not vary with composition linearly.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Giulio Ottonello
Summary: The research shows that the solubility of H2O in CaO-MgO-SiO2-H2O silicate melts at high pressure and temperature is not linear. The application to mantle melting at oceanic ridges suggests that the melting process buffers the oceanic geotherm.
Article
Geochemistry & Geophysics
A. Shatskiy, A. Bekhtenova, A. Arefiev, I. Podborodnikov, K. D. Litasov
Summary: Partial melting of carbonated metapelites at depth can produce two immiscible melts, which are similar to melt inclusions in diamonds. These melts react with garnet lherzolite, resulting in the formation of different minerals. These findings can help interpret the origins and mantle lithological characteristics of melt inclusions in diamonds.
Article
Geosciences, Multidisciplinary
Izumi Mashino, Motohiko Murakami, Shinji Kitao, Takaya Mitsui, Ryo Masuda, Makoto Seto
Summary: This study conducted in situ high-pressure acoustic-wave velocity measurements of Fe2+-bearing MgSiO3 glass to investigate the effect of iron on the elasticity and structural evolution of silicate melts in the lower mantle. The results confirmed the structural transition of Si-O coordination number and suggested that iron decreases the velocity of MgSiO3 glass.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Hugh St C. O'Neill, John A. Mavrogenes
Summary: The solubility of sulfur as sulfate in silicate melts under oxidizing conditions has been experimentally measured, along with the concept of sulfate capacity. By combining sulfate and sulfide capacity, the oxidation states of sulfur in silicate melts can be calculated.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
X-N Liu, R. C. Hin, C. D. Coath, M. van Soest, E. Melekhova, T. Elliott
Summary: This study investigates the issue of elevated magnesium isotope ratios in arc lavas by analyzing the magnesium isotope fractionation between olivine and melt. The results show that primitive arc lavas have similar magnesium isotope ratios to MORB, while evolved arc lavas tend to have isotopically heavier compositions. This variability can be explained by olivine fractionation.
GEOCHEMICAL PERSPECTIVES LETTERS
(2022)
Article
Geochemistry & Geophysics
Zenghao Gao, Ya-Nan Yang, Shui-Yuan Yang, Yuan Li
Summary: The solubility of nitrogen in magmatic melts was investigated through high-pressure experiments. The results showed that nitrogen mainly exists as N2 in silicate melts and its solubility is influenced by pressure and the structure of the melt. An empirical model was developed to predict the solubility of nitrogen and other gases in magmatic melts. This research is important for understanding degassing processes and the formation of nitrogen-rich atmospheres in Earth's interior.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Instruments & Instrumentation
S. Klemme, M. Feldhaus, V Potapkin, M. Wilke, M. Borchert, M. Louvel, A. Loges, A. Rohrbach, P. Weitkamp, E. Welter, M. Kokh, C. Schmidt, D. Testemale
Summary: The new autoclave allows in situ characterization of hydrothermal fluids at high pressures and temperatures using synchrotron x-ray radiation sources. It is specifically designed for x-ray absorption spectroscopy in fluids, with potential applications in mineral solubility and element speciation analysis. Preliminary experiments demonstrate its suitability for studying the behavior of ore-forming metals under relevant P-T conditions in the Earth's crust.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2021)
Article
Geochemistry & Geophysics
Richard W. Thomas, Bernard J. Wood
Summary: Experiments were conducted to investigate the dissolution behavior of chlorine in silicate melts at high pressures and temperatures. The results showed that the initial dissolution mechanism involves the replacement of oxygen ions with chlorine ions in the melt. Chlorine dissolution in different types of basalts follows Henry's Law, with deviations at higher concentrations due to the association of chlorine ions.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Richard W. Thomas, Jon Wade, Bernard J. Wood
Summary: The local bonding environment of chlorine in silicate melts greatly influences the thermodynamic properties and structure of the melt. The addition of divalent cations changes the bonding from covalent to more ionic. The bonding in the glasses is closely related to that found in simple chlorides.
Review
Metallurgy & Metallurgical Engineering
Bjorn Mysen
Summary: This study investigates the coordination states and structures of aluminum in different types of molten silicates, as well as the charge balance with various cations. The distribution and coordination of aluminum in different types of molten silicates vary, indicating a complex relationship between aluminum and other components in the melts.
ISIJ INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Julien Boulliung, Bernard J. Wood
Summary: The sulfur contents of silicate melts were determined under oxidizing conditions, and it was found that sulfur mainly dissolved as sulfate in the melts. The equilibrium sulfur contents were strongly influenced by temperature and compositional parameters. The data provided insights into sulfur degassing processes in ascending silicate melts, showing that SO2 partitions into a fluid phase and most sulfur is lost at high pressures in the crust.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Materials Science, Ceramics
Rasmus R. Petersen, Martin B. Olesen, Jakob Konig, Yuanzheng Yue
Summary: Vermiculite materials are widely used for insulation purposes and fire protection systems. The dimensional stability of vermiculite boards are influenced by the binder and source of vermiculite. When heated, the boards expand and shrink depending on the temperature and board density. The expansion is attributed to the presence of non-expanded particles and metal carbonates, while the shrinkage is caused by dehydroxylation of the clay structure.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
O. N. Koroleva, V. A. Bychinsky, A. A. Tupitcyn
Summary: This study utilized a Gibbs energy minimisation approach to investigate silicate melts of various systems and compositions, including single and mixed alkali systems. The correspondence of the developed models with actual systems was verified by comparing the results with experimental data, establishing the limits of their applicability.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2021)
Article
Multidisciplinary Sciences
Megan Holycross, Elizabeth Cottrell
Summary: Arc magmas are different from mid-ocean ridge magmas in terms of their iron content, oxidation state, and oxygen fugacity. It was previously speculated that garnet crystallization is responsible for these differences, but our experimental results show that garnet does not significantly affect the Fe3+/EFe ratio and fO2 of the melt. Therefore, garnet crystallization is unlikely to explain the oxidized nature of basaltic arc magmas or the Fe-depletion trend observed in continental crust.
Article
Geochemistry & Geophysics
Wen-Pin Hsieh, Enrico Marzotto, Yi-Chi Tsao, Takuo Okuchi, Jung-Fu Lin
Summary: Thermal transport in subducted slabs and mantle is crucial for their thermo-chemical evolution and dynamics. This study investigates the high-pressure thermal conductivities of stishovite and new-hexagonal-aluminous (NAL) phase, and their impacts on slab dynamics. The findings suggest that subducted crustal materials, especially those with local silica-enrichment, have efficient thermal conduction, leading to faster warming of the sinking slab and altering its dynamic stability.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Yanyao Zhang, Suyu Fu, Shun-ichiro Karato, Takuo Okuchi, Stella Chariton, Vitali B. Prakapenka, Jung-Fu Lin
Summary: Seismic studies have identified seismic scatterers with shear velocity anomalies along subducting slabs at certain depths. The post-stishovite transition in subducted mid-ocean ridge basalt has been linked to these anomalies. Experimental data on Al-bearing stishovite crystals revealed a reduction in transition pressure and shear wave velocity due to the presence of aluminum and hydrogen.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Review
Geochemistry & Geophysics
Yanyao Zhang, Stella Chariton, Jiaming He, Suyu Fu, Fang Xu, Vitali B. Prakapenka, Jung-Fu Lin
Summary: In this study, the structural changes of stishovite crystals under high pressure conditions were revealed using synchrotron single-crystal X-ray diffraction. The results show that at a pressure of 51.4 GPa, splitting of O coordinates, crossover of Si-O bond lengths, and rotation of SiO6 octahedra occur. These findings are significant for understanding ferroelastic phase transitions.
AMERICAN MINERALOGIST
(2023)
Article
Multidisciplinary Sciences
Jin Liu, Yang Sun, Chaojia Lv, Feng Zhang, Suyu Fu, Vitali B. Prakapenka, Caizhuang Wang, Kaiming Ho, Jungfu Lin, Renata M. Wentzcovitch
Summary: Oxygen and iron, the most abundant elements on Earth, play crucial roles in planet formation. The existence of oxygen in the solid inner core is still debated, but understanding it is important for co-evolution and the generation of the geomagnetic field. In experiments, iron reacts with FeO and Fe2O3 to form a series of stable stoichiometric FenO compounds. These findings provide new insights into the seismic features of the inner core, the formation process and composition of the inner core, and the thermal evolution of planets.
Article
Chemistry, Multidisciplinary
Jonghoon Lee, Kyeong-Yoon Baek, Jeongjae Lee, Heebeom Ahn, Yongjin Kim, Hyungbin Lim, Yeeun Kim, Jaeyong Woo, Samuel D. Stranks, Sung Keun Lee, Henning Sirringhaus, Keehoon Kang, Takhee Lee
Summary: Organic metal-halide perovskites (OHPs) are attracting attention as next-generation semiconducting materials, but current doping methods have limitations. This study successfully included a molecular dopant into 2D Ruddlesden-Popper perovskites, increasing electrical current by about 60 times while maintaining a clean film surface. The mechanism of immersion doping, where a solvent molecule facilitates bulk diffusion of the dopant molecule, is provided. This method enables bulk molecular doping in OHPs and can be used to control their electrical properties for electronic and optoelectronic devices.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Geochemistry & Geophysics
Suyu Fu, Yanyao Zhang, Takuo Okuchi, Jung-Fu Lin
Summary: This study investigates the thermoelastic properties of mantle candidate minerals and reveals the single-crystal elastic moduli of (Al,Fe)-bearing bridgmanite. It discusses the effects of pressure and composition on the elastic properties, which are important for understanding the geophysical, geochemical, and geodynamic evolutions of the silicate Earth.
AMERICAN MINERALOGIST
(2023)
Article
Physics, Applied
S. Sawada, K. Okai, H. Fukui, R. Takahashi, N. Ishimatsu, H. Maruyama, N. Kawamura, S. Kawaguchi, N. Hirao, T. Seki, K. Takanashi, S. Ohmura, H. Wadati
Summary: We investigated the relationship between lattice constant and magnetism of L1(0)-ordered FePt under high pressure using first-principles calculations and synchrotron x-ray measurements. Our calculations showed a local maximum of the c/a ratio at around 20 GPa, and the Pt magnetic moment remained almost unchanged until around 60 GPa before sharply decreasing. Experimentally, we verified the local maximum of c/a at around 20 GPa through powder x-ray diffraction and observed no significant change in Pt magnetic moment up to around 20 GPa using x-ray magnetic circular dichroism at the Pt L edge.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Shujia Li, Jin Jung Kweon, Seoyoung Lee, A. Chim Lee, Sung Keun Lee
Summary: We have successfully obtained high-resolution NMR spectra of oxide glasses compressed by diamond anvil cells at room temperature, extending the pressure range of previous studies. Our results reveal the densification path through coordination transformation of Al cations in oxide glasses, and quantify the stepwise changes in the Al fractions and the effects of network polymerization on densification paths using a statistical thermodynamic model. These findings broaden our knowledge on the densification of glasses under previously unattainable pressure conditions and contribute to our understanding of the origin of mechanical strengthening in glasses.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Sung Keun Lee, Yoosoo Yi, Yong-Hyun Kim, Hyo-im Kim, Paul Chow, Yuming Xiao, Peter Eng, Guoyin Shen
Summary: Diamond's unprecedented hardness is due to its electronic bonding nature under extreme pressure, which has been experimentally observed through inelastic x-ray scattering spectra measurements up to 2 million atmospheres. The observed changes in electronic structure reveal the ability of diamond to withstand deformation and internal stress, shedding light on the origin of its hardness.
Article
Physics, Applied
Jin Shimada, Atsushi Tani, Takeshi Yamada, Takeshi Sugahara, Takayuki Hirai, Takuo Okuchi
Summary: The dynamics of water molecules in tetra-n-butyl-d36-ammonium bromide semiclathrate hydrate were studied, revealing a fast reorientation motion of water molecules in the temperature range of 212-278 K. The mean jump distance of hydrogen atoms was found to be within 1.5-2.0A degrees, with a relaxation time of 100-410 ps and an activation energy of 10.2 +/- 5.8 kJ/mol. This short relaxation time is possibly due to the strong interaction between a bromide anion and its surrounding water molecules, suggesting a unique strategy for designing efficient, safe, and inexpensive proton conductors using semiclathrate hydrates.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Hyungbin Lim, Kyeong-Yoon Baek, Jae Il Kim, Jonghoon Lee, Jaeyoung Kim, Heebeom Ahn, Hyeonmin Choi, Seung-Je Woo, Sung Keun Lee, Tae-Woo Lee, Jeongjae Lee, Keehoon Kang, Takhee Lee
Summary: Metal-halide perovskites with synthetic tunability can control the crucial properties for optoelectronic device applications. By adjusting the halide compositions, the optical band gap of perovskites can be modified to emit visible light in a wide range of colors. In this study, we successfully synthesized a series of mixed-halide zero-dimensional perovskites using mechanochemical synthesis, and demonstrated their unique optical properties. Moreover, we showed that these perovskite powder samples can be used for fabricating thin films via vacuum deposition. Overall, our research reveals the versatility of mechanochemical synthesis in preparing different compositions of zero-dimensional perovskites.
CHEMISTRY OF MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Hiroshi Fukui, Daisuke Ishikawa, Taishun Manjo, Nozomu Hiraoka, Takashi Taniguchi, Alfred Q. R. Baron
Summary: The effects of boron isotope enrichment on cubic boron nitride (cBN) were investigated. X-ray Raman scattering spectra and meV-resolved inelastic x-ray scattering were used to study the phonon dispersion. The results revealed that the shifts in phonon frequencies were mainly due to the isotope effect of boron enrichment.
Article
Materials Science, Multidisciplinary
K. Katagiri, N. Ozaki, D. Murayama, K. Nonaka, Y. Hironaka, Y. Inubushi, K. Miyanishi, H. Nakamura, T. Okuchi, T. Sano, Y. Seto, K. Shigemori, K. Sueda, T. Togashi, Y. Umeda, M. Yabashi, T. Yabuuchi, R. Kodama
Summary: The Hugoniot equation-of-state, Gruneisen parameter, and structure of laser-shocked polyimide were measured. The results showed that the polyimide has a low melting pressure and rapid melting kinetics.