Field-induced quantum first-order transition in a two-dimensional frustrated antiferromagnet

Fujihara, Masayoshi; Hagihara, Masato; Ishikado, Motoyuki*; Sari, D. P.*; Watanabe, Isao*; Higemoto, Wataru; Tabata, Chihiro; Kaneko, Koji

Physical Review B, 113(6), p.064409_1 - 064409_8, 2026/02

https://doi.org/10.1103/7nqp-9m4x

Possible field-induced quantum state in a rhombic lattice antiferromagnet KCoPOHO

Fujihara, Masayoshi; Hagihara, Masato; Koda, Akihiro*; Nakamura, Jumpei*; Matsuo, Akira*; Kindo, Koichi*; Ishikado, Motoyuki*

Physical Review Materials (Internet), 9(1), p.014406_1 - 014406_9, 2025/01

https://doi.org/10.1103/PhysRevMaterials.9.014406

Antiferromagnetic ordering and chiral crystal structure transformation in NdRhSn

Shimoda, Ami*; Iwasa, Kazuaki*; Kuwahara, Keitaro*; Sagayama, Hajime*; Nakao, Hironori*; Ishikado, Motoyuki*; Nakao, Akiko*; Kawamura, Seiko; Murai, Naoki; Ohara, Takashi; et al.

Physical Review B, 109(13), p.134425_1 - 134425_10, 2024/04

https://doi.org/10.1103/PhysRevB.109.134425

Spin dependence in the -wave resonance of +

Okudaira, Takuya*; Nakabe, Rintaro*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Gudkov, V.*; Ide, Ikuo*; Ino, Takashi*; Ishikado, Motoyuki*; Kambara, Wataru*; et al.

Physical Review C, 109(4), p.044606_1 - 044606_9, 2024/04

https://doi.org/10.1103/PhysRevC.109.044606

Magnetic ordering and structural phase transitions of NdSn ( = Rh and Ir)

Shimoda, Ami*; Iwasa, Kazuaki*; Kuwahara, Keitaro*; Sagayama, Hajime*; Nakao, Hironori*; Ishikado, Motoyuki*; Ohara, Takashi; Nakao, Akiko*; Hoshikawa, Akinori*; Ishigaki, Toru*

JPS Conference Proceedings (Internet), 38, p.011091_1 - 011091_6, 2023/05

https://doi.org/10.7566/JPSCP.38.011091

Energy resolution and neutron flux of the 4SEASONS spectrometer revisited

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Iida, Kazuki*; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Inamura, Yasuhiro; Ishikado, Motoyuki*

Journal of Neutron Research, 22(2-3), p.99 - 107, 2020/10

https://doi.org/10.3233/JNR-200146

=0 long-range magnetic order in centennialite CaCu(OD)Cl 0.6DO; A Spin- perfect kagome antiferromagnet with --

Iida, Kazuki*; Yoshida, Hiroyuki*; Nakao, Akiko*; Jeschke, H. O.*; Iqbal, Y.*; Nakajima, Kenji; Kawamura, Seiko; Munakata, Koji*; Inamura, Yasuhiro; Murai, Naoki; et al.

Physical Review B, 101(22), p.220408_1 - 220408_6, 2020/06

https://doi.org/10.1103/PhysRevB.101.220408

Crystal and magnetic structures of the mineral centennialite CaCu(OD)Cl 0.6DO are investigated by means of synchrotron X-ray diffraction and neutron diffraction measurements complemented by density functional theory (DFT) and pseudofermion functional renormalization group (PFFRG) calculations. In CaCu(OD)Cl 0.6DO, Cu ions form a geometrically perfect kagome network with antiferromagnetic . No intersite disorder between Cu and Ca ions is detected. CaCu(OD)Cl 0.6DO enters a magnetic long-range ordered state below = 7.2 K, and the =0 magnetic structure with negative vector spin chirality is obtained. The ordered moment at 0.3 K is suppressed to 0.58(2)B. Our DFT calculations indicate the presence of antiferromagnetic and ferromagnetic superexchange couplings of a strength which places the system at the crossroads of three magnetic orders (at the classical level) and a spin- PFFRG analysis shows a dominance of =0 type magnetic correlations, consistent with and indicating proximity to the observed =0 spin structure. The results suggest that this material is located close to a quantum critical point and is a good realization of a -- kagome antiferromagnet.

Successive phase transitions in IrSn (: La and Ce) investigated using neutron and X-ray diffraction

Nakazato, Seiya*; Iwasa, Kazuaki*; Hashimoto, Daisuke*; Shiozawa, Mami*; Kuwahara, Keitaro*; Nakao, Hironori*; Sagayama, Hajime*; Ishikado, Motoyuki*; Ohara, Takashi; Nakao, Akiko*; et al.

JPS Conference Proceedings (Internet), 30, p.011128_1 - 011128_6, 2020/03

https://doi.org/10.7566/JPSCP.30.011128

Q dependence of magnetic resonance mode on FeTeSe studied by inelastic neutron scattering

Ishikado, Motoyuki*; Kodama, Katsuaki; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Ji, S.*; Arai, Masatoshi*; Shamoto, Shinichi

Condensed Matter (Internet), 4(3), p.69_1 - 69_10, 2019/09

https://doi.org/10.3390/condmat4030069

The enhancement magnetic resonance mode of FeTeSe is limited around Q = (, 0). Q dependence is found to be consistent with a theoretical simulation of the magnetic resonance mode with the sign-reversing order parameter of swave.

Cryogenic sample environments shared at the MLF, J-PARC

Kawamura, Seiko; Takahashi, Ryuta*; Ishikado, Motoyuki*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ouchi, Keiichi*; Kira, Hiroshi*; Kambara, Wataru*; Aoyama, Kazuhiro*; Sakaguchi, Yoshifumi*; et al.

Journal of Neutron Research, 21(1-2), p.17 - 22, 2019/05

https://doi.org/10.3233/JNR-190106

The Cryogenics and Magnets group in the Sample Environment team is responsible for operation of cryostats and magnets for user's experiments at the MLF in J-PARC. We have introduced a top-loading He cryostat, a bottom-loading He cryostat, a dilution refrigerator insert and a superconducting magnet. The frequency of use of them dramatically becomes higher in these two years, as the beam power and the number of proposal increase. To respond such situation, we have made efforts to enhance performance of these equipment as follows. The He cryostat originally involves an operation software for automatic initial cooling down to the base temperature and automatic re-charge of He. Recently we made an additional program for automatic temperature control with only the sorb heater. Last year, a new outer vacuum chamber of the magnet with an oscillating radial collimator (ORC) was fabricated. The data quality was drastically improved by introducing this ORC so that the magnet can be used even for the inelastic neutron scattering experiments.