Ice IV from supercooled water; Reproducible crystallization, structure, and ordering

Kobayashi, Hiroki*; Komatsu, Kazuki*; Ito, Hayate*; Machida, Shinichi*; Hattori, Takanori; Kagi, Hiroyuki*

Journal of Physical Chemistry C, 130(25), p.8795 - 8805, 2026/06

https://doi.org/10.1021/acs.jpcc.6c00737

Ice IV, a metastable high-pressure phase of ice, rarely crystallizes from water and has therefore been called by a nickname, "will-o'-the-wisp," a tentative, ghostly form of ice. Here we report by experiments using water-in-oil emulsions that liquid water reproducibly and selectively crystallizes into ice IV at the homogeneous nucleation temperature () at pressures between 0.45 and 1.1 GPa. By tracking pressure-induced melting of ice Ih and immediate recrystallization, we show that liquid water preferentially crystallizes into ice IV even below . Thanks to high hydrostaticity and suppressed crystal growth in emulsified ice samples, reliable structure analyses for both ice IV and its potentially hydrogen-ordered state were achieved by neutron diffraction. The achievable degree of ordering in experiments was extremely low and nearly independent of the crystallization methods.

Sommerfeld coefficient enhancement and magnetic short-range order in a hyperkagome 3 system

Shamoto, Shinichi*; Yasui, Yukio*; Yoshizawa, Kanako*; Noda, Yukio*; Takahashi, Miwako*; Onuki, Yoshichika*; Haga, Yoshinori; Ishikado, Motoyuki*; Yamauchi, Hiroki; Huang, T.-C.*; et al.

Physical Review B, 113(23), p.235126_1 - 235126_7, 2026/06

https://doi.org/10.1103/m5pw-ghz3

Fast local motions and their transitions in polybutadiene across the glass transition

Kikuchi, Tatsuya*; Mashita, Ryo*; Masui, Tomomi*; Kanaya, Toshiji*; Kishimoto, Hiroyuki*; Nakajima, Kenji

Physical Review E, 113(6), p.065418_1 - 064518_10, 2026/06

https://doi.org/10.1103/tg7v-hw13

We investigated the local dynamics of polybutadiene over a wide temperature range, using quasielastic neutron scattering combined in the modified mode distribution analysis. Among these processes, the subpicosecond fast process was analyzed using a local diffusion model, which characterizes the dynamics via two physically meaningful parameters: the local diffusion coefficient and the harmonic potential stiffness. Temperature-dependent analysis revealed a distinct dynamic transition near the glass transition, which is interpreted as the disappearance of cooperative diffusion involving multiple segments. Furthermore, an additional relaxation mode, termed the extra-fast process, was identified and interpreted as a higher-order mode within the local diffusion model. These findings suggest a unified physical framework for the evolution of local motions across the glass transition and establish a robust methodology for quantifying polymer dynamics at subnanometer and subpicosecond scales.

Design of a storage ring based on a fixed-field alternating-gradient configuration with an internal target for heavy-ion beams with stochastic charge state conversions

Ishi, Yoshihiro*; Uesugi, Tomonori*; Mori, Yoshiharu*; Nishio, Katsuhisa

Physical Review Accelerators and Beams (Internet), 29(5), p.050101_1 - 050101_14, 2026/05

https://doi.org/10.1103/th5l-mq3q

Spontaneous magnetization curve of -iron at high pressures determined using neutron diffraction

Aoki, Katsutoshi*; Takano, Masahiro*; Fukuyama, Ko*; Kagi, Hiroyuki*; Machida, Akihiko*; Saito, Hiroyuki*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*

Physical Review B, 113(18), p.184440_1 - 184440_6, 2026/05

https://doi.org/10.1103/vdnz-y1nk

The temperature dependence of the magnetic moment of bcc -iron was investigated over the range 300-950 K at pressures of approximately 2 and 6 GPa by neutron powder diffraction. The Fe isotope, whose neutron scattering length is approximately half that of naturally abundant Fe, was employed to enhance the relative contribution of magnetic scattering. Curie temperatures () were determined to be 946(30) K, 838(50) K and 740(40) K at 2.1, 6.0 and 6.7 GPa, respectively, defining a magnetic phase boundary described by (K) = 1043 - 49(7) + 1.3(1.2). Upon heating at 6.7 GPa, the structural transition was observed to follow the magnetic transition. This transition sequence indicates that the magnetic phase boundary lies on the low-temperature side of the phase boundary. Accordingly, the transition corresponds to a structural transformation from paramagnetic bcc to paramagnetic fcc iron.

Magnetization process of the layered diluted ferromagnetic semiconductor (Ba,K)(Zn,Mn)As studied by X-ray magnetic circular dichroism

Wan, Y.*; Shibata, Goro; Takeda, Yukiharu*; Okane, Tetsuo; Saito, Yuji; Yamagami, Hiroshi; Fujimori, Atsushi*; 10 of others*

Physical Review Materials (Internet), 10(5), p.054402_1 - 054402_8, 2026/05

https://doi.org/10.1103/69sm-fz7z

Construction of a Compton camera-equipped robotic system capable of moving autonomously towards the radiation source

Sato, Yuki; Kakuto, Takeshi*; Tanaka, Takayuki*; Shimano, Hiroyuki*

European Physical Journal; Special Topics, 235(4), p.949 - 958, 2026/04

https://doi.org/10.1140/epjs/s11734-025-01483-5

Possible pairing symmetry of BaPtAsSb with an ordered honeycomb network

Imazu, Tsuyoshi; Furutani, Naoya*; Adachi, Tadashi*; Kudo, Kazutaka*; Imai, Yoshiki*; Goryo, Jun*

Journal of the Physical Society of Japan, 95(4), p.044704_1 - 044704_7, 2026/04

https://doi.org/10.7566/JPSJ.95.044704

no abstracts in English

Field-induced antiferromagnetic transition in CeIrIn

Tokunaga, Yo; Suzuki, Michito*; Krmer, S.*; Sakai, Hironori; Kambe, Shinsaku; Harima, Hisatomo*; Aoki, Dai*; Horvati, M.*; Sheikin, I.*

Physical Review B, 113(14), p.L140406_1 - L140406_7, 2026/04

https://doi.org/10.1103/8khb-593t

Josephson diode effect via a nonequilibrium Rashba system

Mori, Michiyasu; Koshibae, Wataru*; Maekawa, Sadamichi*

Physical Review B, 113(13), p.134505_1 - 134505_8, 2026/04

https://doi.org/10.1103/nt1m-5sff