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under hydrostatic pressure; A Combined neutron, X-ray, Raman, and first-principles calculation studyEfthimiopoulos, I.*; Klotz, S.*; Kunc, K.*; Baptiste, B.*; Chauvigne, P.*; Hattori, Takanori
Physical Review B, 111(13), p.134103_1 - 134103_13, 2025/04
We present a comprehensive study of the high pressure behaviour of ReO using X-ray and neutron diffraction, Raman scattering and first-principles calculations to 15 GPa. We show that the ambient pressure 
structure converts at 0.7 GPa in a continuous phase transition directly to a cubic phase with space group 
and rhombohedral 
structures in this pressure range are an artifact due to an alteration of the sample by high-flux synchrotron X-ray radiation. The structural pressure dependence of the 
O samples are presented. The data shed light onto the unusual transition and densification mechanism due to progressive tilting of essentially rigid ReO
octahedra.
GeTe
to hydrostatic pressureWang, Y.*; Zeng, X.-T.*; Li, B.*; Su, C.*; Hattori, Takanori; Sheng, X.-L.*; Jin, W.*
Chinese Physics B, 34(4), p.046203_1 - 046203_6, 2025/03
Times Cited Count：0Two-dimensional van der Waals ferromagnet FeGeTe (FGT) holds a great potential for applications in spintronic devices, due to its high Curie temperature, easy tunability, and excellent structural stability in air. In this study, we have performed high-pressure neutron powder diffraction (NPD) up to 5 GPa, to investigate the evolution of its structural and magnetic properties with hydrostatic pressure. The NPD data clearly reveal the robustness of the ferromagnetism in FGT, despite of an apparent suppression by hydrostatic pressure. As the pressure increases from 0 to 5 GPa, the Curie temperature is found to decrease monotonically from 225(5) K to 175(5) K, together with a dramatically suppressed ordered moment of Fe, which is well supported by the first-principles calculations. Although no pressure-driven structural phase transition is observed up to 5 GPa, quantitative analysis on the changes of bond lengths and bond angles indicate a significant modification of the exchange interactions, which accounts for the pressure-induced suppression of the ferromagnetism in FGT.
Okazaki, Nobuo*; Hattori, Takanori
CROSS Reports (Internet), 3, p.001_1 - 001_8, 2025/02
There have been requests for remote analysis of measured data at the BL11 PLANET beamline in the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), but a system to perform this analysis on a regular basis has not been established. In order to meet this demand, a system for remote analysis was established using NoMachine, which is widely used as a remote desktop connection environment. This system is built on the cloud, and users can analyze data from anywhere with an Internet environment by using the NoMachine client.
Yang, X.*; Che, G.*; Wang, Y.*; Zhang, P.*; Tang, X.*; Lang, P.*; Gao, D.*; Wang, X.*; Wang, Y.*; Hattori, Takanori; et al.
Nano Letters, 25(3), p.1028 - 1035, 2025/01
Times Cited Count：0 Percentile：0.00(Chemistry, Multidisciplinary)Saturated sp
-carbon nanothreads (CNTh) have garnered significant interest due to their predicted high Young's modulus and thermal conductivity. While the incorporation of heteroatoms into the central ring has been shown to influence the formation of CNTh and yield chemically homogeneous products, the impact of pendant groups on the polymerization process remains underexplored. In this study, we investigate the pressure-induced polymerization of phenol, revealing two phase transitions occurring below 0.5 and 4 GPa. Above 20 GPa, phenol polymerizes into degree-4 CNThs featuring hydroxyl and carbonyl groups. Hydrogen transfer of hydroxyl groups was found to hinder the formation of degree-6 nanothreads. Our findings highlight the crucial role of the hydroxyl group in halting further intracolumn polymerization and offer valuable insights for future mechanism research and nanomaterial synthesis.
Che, G.*; Fei, Y.*; Tang, X.*; Zhao, Z.*; Hattori, Takanori; Abe, Jun*; Wang, X.*; Ju, J.*; Dong, X.*; Wang, Y.*; et al.
Physical Chemistry Chemical Physics, 27(2), p.1112 - 1118, 2025/01
Times Cited Count：1 Percentile：0.00(Chemistry, Physical)Pressure-induced polymerization (PIP) of aromatic molecules has emerged as an effective method for synthesizing various carbon-based materials. In this work, PIP of 1,4-difluorobenzene (1,4-DFB) was investigated. 
high-pressure investigations of 1,4-DFB reveal a phase transition at approximately 12.0 GPa and an irreversible chemical reaction at 18.7 GPa. Structural analysis of the product and the kinetics of the reaction uncovered the formation of pseudohexagonal stacked fluoro-diamond nanothreads with linear growth. Compared to the crystal structures of benzene under high pressure, 1,4-DFB exhibits higher compression along the [001] axis. The anisotropic compression is attributed to the stronger H
interaction along the [01
] axis and the potential compression-inhibiting H
F interactions along the [100] and [010] axes, and it facilitates a possible reaction pathway along the [01] axis. This work emphasizes the crucial role of functionalization in modulating molecular stacking and influencing the reaction pathway.
Xu, J.*; Lang, P.*; Liang, S.*; Zhang, J.*; Fei, Y.*; Wang, Y.*; Gao, D.*; Hattori, Takanori; Abe, Jun*; Dong, X.*; et al.
Journal of Physical Chemistry Letters (Internet), p.2445 - 2451, 2025/00
Times Cited Count：0The Alder-ene reaction is a chemical reaction between an alkene with an allylic hydrogen, and it provides an efficient method to construct the C-C bond. Traditionally, this reaction requires catalysts, high temperatures, or photocatalysis. In this study, we reported a high-pressure-induced solid-state Alder-ene reaction of 1-hexene at room temperature without a catalyst. 1-Hexene crystallizes at 4.3 GPa and polymerizes at 18 GPa, forming olefins. By exploring gas chromatography-mass spectrometry, we discovered that 1-hexene generates dimeric products through the Alder-ene reaction under high pressures. The in situ neutron diffraction shows that the reaction process did not obey the topochemical rule. A six-membered ring transition state including one C-H 
bond and two alkene 
bonds was evidenced by the theoretical calculation, whose energy obviously decreased when compressed to 20 GPa. Our work offers a novel and promising method to realize the Alder-ene reaction at room temperature without a catalyst, expanding the application of this important reaction.
Yamashita, Keishiro*; Komatsu, Kazuki*; Hattori, Takanori; Machida, Shinichi*; Kagi, Hiroyuki*
Acta Crystallographica Section B; Structural Science, Crystal Engineering and Materials (Internet), 80(6), p.695 - 705, 2024/12
Times Cited Count：0 Percentile：0.00(Chemistry, Multidisciplinary)So far, the odd hydration number has been missing in the water-rich magnesium chloride hydrate series (MgCl
HO). In this study, we have identified magnesium chloride heptahydrate, MgCl7HO (or MgCl7DO) which forms at high pressures and high temperatures of above 2 GPa and above 300 K, respectively. Its structure has been determined by a combination of 
single crystal X-ray diffraction at 2.5 GPa and 298 K and powder neutron diffraction at 3.1 GPa and 300 K. The results showed an orientational disorder of water molecules, which was also examined by the density-functional-theory calculations. The disorder involves the reconnection of hydrogen bonds, which differs from those in water ice phases and known disordered salt hydrates. The shrinkage by compression occurs mainly in one direction. In the plane perpendicular to this most compressible direction, oxygen and chlorine atoms are in a hexagonal-like arrangement.
Hattori, Takanori; Komatsu, Kazuki*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 66(12), p.618 - 622, 2024/12
The high-pressure neutron diffractometer PLANET is the first beamline dedicated to high-pressure neutron experiments in Japan. It was constructed at the Materials and Life Science Experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC) located at Tokai-mura in Ibaraki Prefecture. Energy-dispersive data measurement using pulsed neutrons, state-of-the-art optical instruments, and a high-pressure device enable us to analyze the structure of crystals, liquids, and glasses over a wide range of pressure and temperature with unprecedented accuracy. In this paper, we will show how this has been achieved and introduce the recently published results on the symmetrization of hydrogen bonds in ice.
Machida, Akihiko*; Saito, Hiroyuki*; Sugimoto, Hidehiko*; Hattori, Takanori; Sano, Asami; Endo, Naruki*; Katayama, Yoshinori*; Iizuka, Riko*; Sato, Toyoto*; Matsuo, Motoaki*; et al.
Nature Communications (Internet), 15, p.8861_1 - 8861_2, 2024/10
Times Cited Count：0 Percentile：0.00(Multidisciplinary Sciences)In our previous article (Nature Commun. 5, 5063 (2014)), the site occupancies of D atoms dissolved in an fcc Fe metal lattice were investigated via Rietveld refinement of neutron powder diffraction patterns collected at 988 K and 6.3 GPa. The fcc metal lattice has two interstitial sites available for accommodating D atoms: octahedral and tetrahedral sites. The Rietveld refinement revealed that D atoms occupied mainly the octahedral sites with occupancy of 0.532 and slightly the tetrahedral sites with occupancy of 0.056. Subsequent density-functional-theory (DFT) calculations by Antonov (Phys. Rev. Mater. 2019)) showed that the occupation energy on the tetrahedral site was significantly higher than that on the octahedral site; the tetrahedral site occupation was unlikely to occur even at temperatures as high as 988 K. We reexamined the site occupancies of D-atom by Rietveld refinement including extinction correction. As a result, the octahedral occupancy was increased to 0.60 and the tetrahedral occupancy was reduced to zero. The occupation of only the octahedral site for D atom is consistent with the DFT calculation, although in contrast to the previous results.
Machida, Shinichi*; Hattori, Takanori; Nakano, Satoshi*; Sano, Asami; Funakoshi, Kenichi*; Abe, Jun*
Koatsuryoku No Kagaku To Gijutsu, 34(3), p.134 - 142, 2024/09
A diamond anvil cell (DAC) for high-pressure neutron diffraction experiments has been developed at the PLANET beamline, Materials and Life Science Experimental Facility, in J-PARC. The conically supported diamond anvils were used for high-pressure generation. We succeeded in obtaining the neutron data for DO ice up to 69.4 GPa. In addition, the gasket materials suitable for the neutron diffraction measurements were investigated. 11 kinds of alloys were tested and SUS304, Inconel718 and M2052 (73Mn-20Cu-5Ni-2Fe, at%) alloys showed excellent performance. Especially, M2052 null-matrix alloy has proven to be useful for neutron diffraction experiments where the beam inevitably hits the gasket. We then obtained refinable neutron diffraction profiles in Rietveld analysis from DO ice at least up to 43.3 GPa.
S under pressureKosaka, Yusuke*; Oishi, Kazuki*; Hattori, Takanori
Koatsuryoku No Kagaku To Gijutsu, 34(3), p.121 - 126, 2024/09
Transition-metal intercalated dichalcogenides have attracted attention due to the observation of chiral helimagnetism (CHM) and chiral soliton lattice in CrNbS. It forms a chiral monoaxial crystal structure with a space group P622. To examine the pressure effect on the CHM period of CrNbS, we performed small-angle neutron scattering experiments with a piston-cylinder pressure cell up to 1.2 GPa. We observed a decrease in the magnetic transition temperature with increasing pressure. Moreover, the CHM period decreased with increasing pressure. Compared to the decrease of the lattice constant, that of the CHM period is much larger. This indicates that applying pressure weakens the amplitude of Dzyaloshinskii-Moriya interaction.
-
transitionsYang, Q.*; Yang, X.*; Wang, Y.*; Fei, Y.*; Li, F.*; Zheng, H.*; Li, K.*; Han, Y.*; Hattori, Takanori; Zhu, P.*; et al.
Nature Communications (Internet), 15, p.7778_1 - 7778_9, 2024/09
Times Cited Count：6 Percentile：84.39(Multidisciplinary Sciences)Luminescent materials that simultaneously embody bright singlet and triplet excitons hold great potential in optoelectronics, signage, and information encryption. However, achieving high-performance white-light emission is severely hampered by their inherent unbalanced contribution of fluorescence and phosphorescence. Herein, we address this challenge by pressure treatment engineering via hydrogen bonding cooperativity effect to realize the mixture of n-- transitions, where the triplet state emission was boosted from 7% to 40% in isophthalic acid (IPA). A superior white-light emission based on hybrid fluorescence and phosphorescence was harvested in pressure-treated IPA, and the photoluminescence quantum yield was increased to 75% from the initial 19% (blue-light emission). In-situ high-pressure IR spectra, X ray diffraction, and neutron diffraction reveal continuous strengthening of the hydrogen bonds with the increase of pressure. Furthermore, this enhanced hydrogen bond is retained down to the ambient conditions after pressure treatment, awarding the targeted IPA efficient intersystem crossing for balanced singlet/triplet excitons population and resulting in efficient white-light emission. This work not only proposes a route for brightening triplet states in organic small molecule, but also regulates the ratio of singlet and triplet excitons to construct high-performance white-light emission.
He, X.*; Kagi, Hiroyuki*; Komatsu, Kazuki*; Iizuka, Riko*; Okajima, Hajime*; Hattori, Takanori; Sano, Asami; Machida, Shinichi*; Abe, Jun*; Goto, Hirotada*; et al.
Journal of Molecular Structure, 1310, p.138271_1 - 138271_8, 2024/08
Times Cited Count：0 Percentile：0.00(Chemistry, Physical)High-pressure responses of the O-D
F hydrogen bonds in deuterated magnesium hydroxyfluoride were investigated using neutron powder diffraction and Raman spectroscopy. The Rietveld analysis at ambient conditions revealed a chemical formula of Mg(OD)
F
and hydroxyl group/fluorine disorder (OD/F disorder) in the crystal structure, which gave rise to two hydrogen-bonding configurations. The Rietveld analysis showed the hydrogen-bonding geometries remains up to 9.8 GPa, indicating no pressure-induced strengthening of hydrogen bonds. The Raman spectra at ambient conditions showed three hydroxyl stretching bands at 2613, 2694, and 2718 cm
. The high frequencies of the O-D stretching modes indicated that the hydroxyls should be involved in weak or none hydrogen-bonding interactions. Up to 20.2 GPa, the mode initially centered at 2694 cm displayed a pressure-induced blue shift, revealing no strengthening of hydrogen bonds under compression. We discuss the existence of hydrogen bonds and the causes of the blue-shifting hydroxyls at ambient and at high pressures.
Zhang, Z.*; Hattori, Takanori; Song, R.*; Yu, D.*; Mole, R.*; Chen, J.*; He, L.*; Zhang, Z.*; Li, B.*
Journal of Applied Physics, 136(3), p.035105_1 - 035105_8, 2024/07
Times Cited Count：1 Percentile：53.26(Physics, Applied)Solid-state refrigeration using barocaloric materials is environmentally friendly and highly efficient, making it a subject of global interest over the past decade. Here, we report giant barocaloric effects in sodium hexafluorophosphate (NaPF) and sodium hexafluoroarsenate (NaAsF) that both undergo a cubic-to-rhombohedral phase transition near room temperature. We have determined that the low-temperature phase structure of NaPF is a rhombohedral structure with space group R
and NaAsF, i.e., F
, E
, and A
. The phase transition temperature varies with pressure at a rate of dT
/dP = 250 and 310 K/GPa for NaPF and NaAsF. The pressure-induced entropy changes of NaPF and NaAsF are determined to be around 45.2 and 35.6J kgK, respectively. The saturation driving pressure is about 40 MPa. The pressure-dependent neutron powder diffraction suggests that the barocaloric effects are related to the pressure-induced cubic-to-rhombohedral phase transitions.
Hattori, Takanori; Suzuki, Koji*; Miyo, Tatsuya*; Ito, Takayoshi*; Machida, Shinichi*
Nuclear Instruments and Methods in Physics Research A, 1064, p.169448_1 - 169448_9, 2024/07
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)The authors regret that the abstract and summary explain that the cup diameter of a standard double-toroidal anvils is 1.5 mm. This is incorrect; the standard diameter is 4.0 mm. The authors would like to apologise for any inconvenience caused.
O ice observed by neutron diffractionKomatsu, Kazuki*; Hattori, Takanori; Klotz, S.*; Machida, Shinichi*; Yamashita, Keishiro*; Ito, Hayate*; Kobayashi, Hiroki*; Irifune, Tetsuo*; Shimmei, Toru*; Sano, Asami; et al.
Nature Communications (Internet), 15, p.5100_1 - 5100_7, 2024/06
Times Cited Count：3 Percentile：63.31(Multidisciplinary Sciences)Hydrogen bond symmetrisation is the phenomenon where a hydrogen atom is located at the centre of a hydrogen bond. Theoretical studies predict that hydrogen bonds in ice VII eventually undergo symmetrisation upon increasing pressure, involving nuclear quantum effect with significant isotope effect and drastic changes in the elastic properties through several intermediate states with varying hydrogen distribution. Despite numerous experimental studies conducted, the location of hydrogen and hence the transition pressures reported up to date remain inconsistent. Here we report the atomic distribution of deuterium in DO ice using neutron diffraction above 100 GPa and observe for the first time the transition from a bimodal to a unimodal distribution of deuterium at around 80 GPa. At the transition pressure, a significant narrowing of the peak widths of 110 was also observed, attributed to the structural relaxation by the change of elastic properties.
Hattori, Takanori; Suzuki, Koji*; Miyo, Tatsuya*; Ito, Takayoshi*; Machida, Shinichi*
Nuclear Instruments and Methods in Physics Research A, 1059, p.168956_1 - 168956_9, 2024/02
Times Cited Count：2 Percentile：51.90(Instruments & Instrumentation)Radial collimators (RC) with a 0.5 mm gauge size (GS) were specially designed for high-pressure neutron diffraction experiments and their performance and efficacy were investigated. The RCs with nominal GS of 0.75 mm, 1.5 mm, and 3.0 mm effectively exhibited GS of 0.50 mm, 1.07 mm, and 2.78 mm, respectively. The transmissions of all three RCs were almost equivalent. The assessment using a P-E press and a DAC revealed that the anvil scattering was considerably minimized and the sample-to-anvil signal ratio reached values of 0.5 and 2.0 for the PE press and DAC, respectively, when using the 0.5 mm-GS RCs. These results indicate that the 0.5mm-GS RCs have been fabricated as intended and exhibit efficacy for the high-pressure-neutron diffraction experiments, specifically those exceeding 30 GPa. Among those ever manufactured for neutron scattering experiments, the RCs display the smallest GS.
structure transition under high pressureYamanaka, Takamitsu*; Nakamoto, Yuki*; Sakata, Masafumi*; Shimizu, Katsuya*; Hattori, Takanori
Physics and Chemistry of Minerals, 51(1), p.4_1 - 4_10, 2024/02
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)Neutron and synchrotron X-ray diffraction and electric conductivity measurements of FeTiO ilmenite were performed under pressures. Ilmenite structure is retained up to 28 GPa. Structure analysis revealed that FeO and TiO are compressible and less compressible below 8 GPa, respectively. The resistivity is lowest along the Fe-Ti direction that has shortest interatomic distance among all the metal ion pairs. The resistivity in the direction normal to c-axis monotonically decreases with pressure, whereas that along c-axis shows hallow-shape with pressure. Maximum entropy analysis shows that electron configuration of Fe
(3
) is more strongly changed than Ti
(3
) under compression. The anisotropic electrical conductivity and non-uniform structure change of Fe-Ti interatomic distance can be explained by the possible spin transition from high-spin state to intermediate-spin state of Fe cation.
Okazaki, Nobuo*; Hattori, Takanori
CROSS Reports (Internet), 1, p.001_1 - 001_9, 2023/12
There has been no method for users to monitor the current status of the experiments at BL11 (PLANET) from outside. To solve this, a monitoring system, named RemoShot, has been implemented to capture remotely the screenshots of the control PC. The RemoShot consists of a screenshot control server, a control PC in the beamline, and cloud storage. It operates in the following sequence: 1) Start a screenshot control server on the PC at beamline, 2) The screenshot control server accesses the MLF-side PC (measurement control PC) via SSH authentication and capturesa screenshot, 3) the captured screenshot is stored in cloud storage, and 4) after authentication, users can see the screenshot in the cloud. This system allows users to check the status of their experiments from anywhere using smartphones and other devices, and to quickly revise the experimental plan in case of measurement issuers or sequence delays due to unexpected beam off. We also discussed security and operating costs of this system.
neutron diffractionKobayashi, Hiroki*; Komatsu, Kazuki*; Ito, Hayate*; Machida, Shinichi*; Hattori, Takanori; Kagi, Hiroyuki*
Journal of Physical Chemistry Letters (Internet), 14(47), p.10664 - 10669, 2023/11
Times Cited Count：2 Percentile：32.17(Chemistry, Physical)Ice IV is a metastable high-pressure phase of ice in which the water molecules exhibit orientational disorder. Although orientational ordering is commonly observed for other ice phases, it has not been reported for ice IV. We conducted powder neutron diffraction experiments for DCl-doped D
O ice IV to investigate hydrogen ordering in ice IV. We found abrupt changes in the temperature derivative of unit cell volume, dV/dT, at about 120 K, and revealed their slightly ordered structure at low temperatures based on the Rietveld method. The occupancy of the D1 site deviates from 0.5; it increased when samples were cooled at higher pressures and reached 0.282(5) at 2.38 GPa, 58 K. Our results evidence the presence of a low-symmetry hydrogen-ordered state corresponding to ice IV. It seems, however, difficult to experimentally access the completely ordered phase corresponding to ice IV by slow cooling at high pressure.
