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Journal Articles

Development and application of a $$^3$$He neutron spin filter at J-PARC

Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10

Journal Articles

$$q$$=0 long-range magnetic order in centennialite CaCu$$_{3}$$(OD)$$_{6}$$Cl$$_{2}$$ $$cdot$$ 0.6D$$_{2}$$O; A Spin-$$frac{1}{2}$$ perfect kagome antiferromagnet with $$J_{1}$$-$$J_{2}$$-$$J_{d}$$

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

Crystal and magnetic structures of the mineral centennialite CaCu$$_{3}$$(OD)$$_{6}$$Cl$$_{2}$$ $$cdot$$ 0.6D$$_{2}$$O 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$$_{3}$$(OD)$$_{6}$$Cl$$_{2}$$ $$cdot$$ 0.6D$$_{2}$$O, Cu$$^{2+}$$ ions form a geometrically perfect kagome network with antiferromagnetic $$J_{1}$$. No intersite disorder between Cu$$^{2+}$$ and Ca$$^{2+}$$ ions is detected. CaCu$$_{3}$$(OD)$$_{6}$$Cl$$_{2}$$ $$cdot$$ 0.6D$$_{2}$$O enters a magnetic long-range ordered state below $$T_{rm N}$$ = 7.2 K, and the $$q$$=0 magnetic structure with negative vector spin chirality is obtained. The ordered moment at 0.3 K is suppressed to 0.58(2)$$mu$$B. Our DFT calculations indicate the presence of antiferromagnetic $$J_{2}$$ and ferromagnetic $$J_{d}$$ superexchange couplings of a strength which places the system at the crossroads of three magnetic orders (at the classical level) and a spin-$$frac{1}{2}$$ PFFRG analysis shows a dominance of $$q$$=0 type magnetic correlations, consistent with and indicating proximity to the observed $$q$$=0 spin structure. The results suggest that this material is located close to a quantum critical point and is a good realization of a $$J_{1}$$-$$J_{2}$$-$$J_{d}$$ kagome antiferromagnet.

Journal Articles

Horizontal line nodes in Sr$$_2$$RuO$$_4$$ proved by spin resonance

Iida, Kazuki*; Kofu, Maiko; Suzuki, Katsuhiro*; Murai, Naoki; Kawamura, Seiko; Kajimoto, Ryoichi; Inamura, Yasuhiro; Ishikado, Motoyuki*; Hasegawa, Shunsuke*; Masuda, Takatsugu*; et al.

Journal of the Physical Society of Japan, 89(5), p.053702_1 - 053702_5, 2020/05

 Times Cited Count:1 Percentile:100(Physics, Multidisciplinary)

Journal Articles

Development of the neutron polarizer for the T-violation search using compound nuclei

Okudaira, Takuya; Oku, Takayuki; Sakai, Kenji; Ino, Takashi*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Shinohara, Takenao; Kakurai, Kazuhisa*; Aizawa, Kazuya; Shimizu, Hirohiko*; et al.

Proceedings of Science (Internet), 356, p.029_1 - 029_5, 2019/12

The technology development section carries out the development of the neutron polarization device: $$^{3}$$He Spin Filter. It is often used for the fundamental physics region. In order to explain the matter-dominated universe, a time reversal violation is necessary and searches for new physics are conducted in the world. The T-violation search using a polarized neutron beam is planned at J-PARC. A large $$^{3}$$He spin filter is needed to polarize high energy neutrons for the experiment and is developed in JAEA. Recently, we developed the accurate measurement system to evaluate the polarization of $$^{3}$$He and a vacuum system to make the $$^{3}$$He spin filter, and large $$^{3}$$He spin filters for epi-thermal neutron was made using the system. The current status of the development of the $$^{3}$$He spin filter will be talked.

Journal Articles

Phase-transition kinetics of magnetic skyrmions investigated by stroboscopic small-angle neutron scattering

Nakajima, Taro*; Inamura, Yasuhiro; Ito, Takayoshi*; Oishi, Kazuki*; Oike, Hiroshi*; Kagawa, Fumitaka*; Kikkawa, Akiko*; Taguchi, Yasujiro*; Kakurai, Kazuhisa*; Tokura, Yoshinori*; et al.

Physical Review B, 98(1), p.014424_1 - 014424_5, 2018/07

 Times Cited Count:4 Percentile:50.71(Materials Science, Multidisciplinary)

We investigated the phase-transition kinetics of magnetic skyrmion lattice (SkL) in MnSi by means of stroboscopic small-angle neutron scattering (SANS). Temporal evolutions of SANS patterns were measured with time resolution of 13 ms while sweeping temperature as fast as 50 Ks$$^{-1}$$. It turned out that the paramagnetic-to-SkL transition immediately occurs upon traversing the equilibrium phase boundary on the rapid cooling, whereas the SkL-to-conical transition can be kinetically avoided to realize the low-temperature metastable SkL with a long-range magnetic order. The formation of the metastable SkL was found to be strongly dependent not only on cooling rate, but also on magnetic eld and trajectory in the H-T phase diagram.

Journal Articles

Structure of the magnetic excitations in the spin-1/2 triangular-lattice Heisenberg antiferromagnet Ba$$_{3}$$CoSb$$_{2}$$O$$_{9}$$

Ito, Saya*; Kurita, Nubuyuki*; Tanaka, Hidekazu*; Kawamura, Seiko; Nakajima, Kenji; Ito, Shinichi*; Kuwahara, Keitaro*; Kakurai, Kazuhisa*

Nature Communications (Internet), 8, p.235_1 - 235_6, 2017/08

 Times Cited Count:30 Percentile:6.08(Multidisciplinary Sciences)

Journal Articles

Interaction of spin-orbital-lattice degrees of freedom; Vibronic state of the corner-sharing-tetrahedral frustrated spin system HoBaFe$$_{4}$$O$$_{7}$$ by dynamical Jahn-Teller effect

Kamazawa, Kazuya*; Ishikado, Motoyuki*; Kawamura, Seiko; Kawakita, Yukinobu; Kakurai, Kazuhisa*; Nakajima, Kenji; Sato, Masashi*

Physical Review B, 95(10), p.104413_1 - 104413_7, 2017/03

 Times Cited Count:2 Percentile:78.36(Materials Science, Multidisciplinary)

Journal Articles

Neutron diffraction study of 1D quantum spin system Li$$_{2}$$ZrCuO$$_{4}$$ with incommensurate magnetic structure

Yasui, Yukio*; Igawa, Naoki; Kakurai, Kazuhisa

JPS Conference Proceedings (Internet), 8, p.034012_1 - 034012_6, 2015/09

Magnetic structure has been studied by using neutron diffraction for quasi one-dimensional quantum spin system Li$$_{2}$$ZrCuO$$_{4}$$ with CuO$$_{2}$$ ribbon chains. The CuO$$_{2}$$ ribbon system Li$$_{2}$$ZrCuO$$_{4}$$ exhibits the antiferromagnetic transition at T$$_{N}$$ $$sim$$ 7 K, however, the magnetic transition is not accompanied with ferroelectricity. At 3K, we observed magnetic superlattice reflections at Q = (0, k, l$$pm$$$$delta$$) and (h, 0, l$$pm$$$$delta$$) (h, k and l = even) with $$delta$$$$sim$$ 0.488 by the powder neutron diffraction. By the combined studies of neutron diffraction and magnetization data, the magnetic structure of Li$$_{2}$$ZrCuO$$_{4}$$ is proposed. On the bases of the obtained data, reasons for absence of ferroelectricity in Li$$_{2}$$ZrCuO$$_{4}$$ are discussed.

Journal Articles

Development status of the NMR system for the polarized $$^{3}$$He Neutron Spin Filter (NSF) in the MLF at J-PARC

Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi*; Kira, Hiroshi*; Hiroi, Kosuke; Ino, Takashi*; Oyama, Kenji*; Okawara, Manabu*; Kakurai, Kazuhisa; Shinohara, Takenao; et al.

JPS Conference Proceedings (Internet), 8, p.036015_1 - 036015_6, 2015/09

The polarized $$^{3}$$He filter, which polarizes neutrons due to a large neutron absorption cross section of $$^{3}$$He with strong spin selectivity, becomes a convenient neutron spin filter (NSF) because it is operated immediately after its installation in beam lines without any neutron beam adjustments. For realizing such the NSF, a nuclear magnetic resonance (NMR) system is indispensable for monitoring $$^{3}$$He nuclear spin polarization ${it P}$ of the NSF. We have developed the flexible NMR system based on adiabatic fast passage (AFP) and pulse NMR methods by using their complementary features. In comparing with the values of ${it P}$ obtained by neutron transmission measurement at the beam line 10 of the J-PARC, we measured the correlations between the AFP and pulse NMR signals as changing condition of temperature, amplitude and applying period of the radio frequency field for the pulse NMR, and so on. As the results, we confirmed that our system would function enough as the ${it P}$ monitor.

Journal Articles

Development of portable polarized $$^{3}$$He neutron spin filter and its application to magnetic field imaging at J-PARC

Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi; Kira, Hiroshi*; Shinohara, Takenao; Oikawa, Kenichi; Harada, Masahide; Kakurai, Kazuhisa; Aizawa, Kazuya; Arai, Masatoshi; et al.

Journal of Physics; Conference Series, 528, p.012016_1 - 012016_7, 2014/07

 Times Cited Count:0 Percentile:100

In polarized neutron experiments, it is interested in expanding measurable neutron energy region up to epithermal neutrons. For realizing this situation, a Polarized $$^{3}$$He Spin Flipper (PHSF) has a key role because it can polarize from cold to epithermal neutrons, and flip neutron spins by flipping the $$^{3}$$He nuclear spin direction. We have developed the portable PHSF consisting of a cylindrical glass cell filled with $$^{3}$$He gas which is installed a solenoid coil of 20 cm in diameter and 30 cm long. After polarizing the $$^{3}$$He gas by irradiating a laser light based on a SEOP technique, the PHSF is brought by hands to experimental areas with kept its polarization. We carried out the feasibility test on our portable PHSF in the MLF of J-PARC and demonstrated it worked well by evaluating flipping ratios of polarized neutrons and attempting to visualize magnetic fields generated by sample coils.

Journal Articles

Weak ferromagnetic ordering disordered by Rh$$^{3+}$$ ions for LaCo$$_{0.8}$$Rh$$_{0.2}$$O$$_{3}$$

Asai, Shinichiro*; Okazaki, Ryuji*; Terasaki, Ichiro*; Yasui, Yukio*; Igawa, Naoki; Kakurai, Kazuhisa

JPS Conference Proceedings (Internet), 3, p.014034_1 - 014034_6, 2014/06

We have carried out the neutron scattering measurements for a single crystal of LaCo$$_{0.8}$$Rh$$_{0.2}$$O$$_{3}$$ in order to investigate the ferromagnetic ordering induced by Rh$$^{3+}$$ substitution for Co$$^{3+}$$ of LaCoO$$_{3}$$. The ordered moment is evaluated to be 0.4$$pm$$0.2$$mu$$$$_{B}$$, which is consistent with the saturation magnetization of LaCo$$_{0.8}$$Rh$$_{0.2}$$O$$_{3}$$. It indicates that the ferromagnetic ordering of LaCo$$_{0.8}$$Rh$$_{0.2}$$O$$_{3}$$ originates from the short-range ferromagnetic ordering disordered by Rh$$^{3+}$$ ions.

Journal Articles

Role of magnetic chirality in polarization flip upon a commensurate-incommensurate magnetic phase transition in YMn$$_{2}$$O$$_{5}$$

Wakimoto, Shuichi; Kimura, Hiroyuki*; Sakamoto, Yuma*; Fukunaga, Mamoru*; Noda, Yukio*; Takeda, Masayasu; Kakurai, Kazuhisa

Physical Review B, 88(14), p.140403_1 - 140403_5, 2013/10

 Times Cited Count:17 Percentile:32.4(Materials Science, Multidisciplinary)

Journal Articles

Effects of Mg, Ag, and Al substitutions on magnetic excitations in the triangular-lattice antiferromagnet CuCrO$$_{2}$$

Kajimoto, Ryoichi; Nakajima, Kenji; Kawamura, Seiko; Inamura, Yasuhiro; Kakurai, Kazuhisa; Hokazono, Takahisa*; Ozono, Akira*; Okuda, Tetsuji*

Journal of the Physical Society of Japan, 82(5), p.054702_1 - 054702_6, 2013/05

 Times Cited Count:4 Percentile:60.7(Physics, Multidisciplinary)

Journal Articles

Magnetoelectric effect driven by magnetic domain modification in LuFe$$_{2}$$O$$_{4}$$

Kambe, Takashi*; Fukada, Yukimasa*; Kano, Jun*; Nagata, Tomoko*; Okazaki, Hiroyuki*; Yokoya, Takayoshi*; Wakimoto, Shuichi; Kakurai, Kazuhisa; Ikeda, Naoshi*

Physical Review Letters, 110(11), p.117602_1 - 117602_5, 2013/03

 Times Cited Count:20 Percentile:22.58(Physics, Multidisciplinary)

Journal Articles

Uniaxial-pressure control of magnetic phase transitions in a frustrated magnet CuFe$$_{1-x}$$Ga$$_{x}$$O$$_{2}$$ (x =0, 0.018)

Nakajima, Taro*; Mitsuda, Setsuo*; Takahashi, Keiichiro*; Yoshitomi, Keisuke*; Masuda, Kazuya*; Kaneko, Chikafumi*; Homma, Yuki*; Kobayashi, Satoru*; Kitazawa, Hideaki*; Kosaka, Masashi*; et al.

Journal of the Physical Society of Japan, 81(9), p.094710_1 - 094710_8, 2012/09

Journal Articles

Uniaxial-pressure control of magnetic phase transitions in a frustrated magnet CuFe$$_{1-x}$$Ga$$_{x}$$O$$_{2}$$ ($$x$$ = 0, 0.018)

Nakajima, Taro*; Mitsuda, Setsuo*; Takahashi, Keiichiro*; Yoshitomi, Keisuke*; Masuda, Kazuya*; Kaneko, Chikafumi*; Homma, Yuki*; Kobayashi, Satoru*; Kitazawa, Hideaki*; Kosaka, Masashi*; et al.

Journal of the Physical Society of Japan, 81(9), p.094710_1 - 094710_8, 2012/09

 Times Cited Count:10 Percentile:39.54(Physics, Multidisciplinary)

Journal Articles

Higgs transition from a magnetic Coulomb liquid to a ferromagnet in Yb$$_{2}$$Ti$$_{2}$$O$$_{7}$$

Chang, L.-J.*; Onoda, Shigeki*; Su, Y.*; Kao, Y.-J.*; Tsuei, K.-D.*; Yasui, Yukio*; Kakurai, Kazuhisa; Lees, M. R.*

Nature Communications (Internet), 3, p.992_1 - 992_7, 2012/08

 Times Cited Count:139 Percentile:2.13(Multidisciplinary Sciences)

Journal Articles

Development of polarized Xe gas target for neutron experiment at J-PARC

Sakai, Kenji; Oku, Takayuki; Shinohara, Takenao; Kira, Hiroshi; Oi, Motoki; Maekawa, Fujio; Kakurai, Kazuhisa; Ino, Takashi*; Arimoto, Yasushi*; Shimizu, Hirohiko*; et al.

Journal of Physics; Conference Series, 340, p.012037_1 - 012037_7, 2012/02

 Times Cited Count:2 Percentile:33.74

At the Materials and Life science experimental Facility (MLF) in J-PARC, an experiment of detecting a neutron polarizing ability caused by a neutron-nuclear (n-N) spin correlation term at a resonant peak of $$^{129}$$Xe is planned. The Xe gas having a high polarization under low magnetic field and room temperature by a spin exchange optical pumping (SEOP) technique is expected to become a suitable target for verification of the neutron optical theorem (NOPT). We evaluated measurable quantities based on the NOPT, developed a polarized Xe gas system, and carried out a feasibility test of our apparatus. This paper reports on the present status of the experiment.

Journal Articles

Neutron scattering studies of the spin-5/2 antiferromagnetic linear trimer substance SrMn$$_3$$P$$_4$$O$$_{14}$$

Hase, Masashi*; D$"o$nni, A.*; Ozawa, Kiyoshi*; Kitazawa, Hideaki*; Sakai, Osamu*; Pomjakushin, V. Y.*; Keller, L.*; Kaneko, Koji; Metoki, Naoto; Kakurai, Kazuhisa; et al.

Journal of Physics; Conference Series, 340, p.012066_1 - 012066_7, 2012/00

 Times Cited Count:1 Percentile:51.5

We determined the magnetic structure below $$T_{rm N1}=2.2(1)$$ K of the spin-5/2 antiferromagnetic (AF) trimer substance SrMn$$_3$$P$$_4$$O$$_{14}$$ using neutron powder diffraction experiments. The incommensurate propagation vector is expressed as [0, $$k_y$$, 0], due to competition between the nearest-neighbor and next-nearest-neighbor interactions in trimerized chains. The value of $$k_y$$ is 0.316 to 0.331, changing rapidly at $$T_{rm N2}= 1.75(5)$$ K. We confirmed that the intra-trimer $$J_1$$ interaction is AF. The magnetic excitation peaks were obsereved at 0.46, 0.68, and 1.02 meV. The weak Q dependence indicates the discrete energy levels, which do not contradict the AF trimer model with the intra-trimer interaction value of 0.29 meV (3.4 K).

Journal Articles

Magnetic excitations in the spin-5/2 antiferromagnetic trimer substance SrMn$$_3$$P$$_4$$O$$_{14}$$

Hase, Masashi*; Matsuda, Masaaki*; Kaneko, Koji; Metoki, Naoto; Kakurai, Kazuhisa; Yang, T.*; Cong, R.*; Lin, J.*; Ozawa, Kiyoshi*; Kitazawa, Hideaki*

Physical Review B, 84(21), p.214402_1 - 214402_6, 2011/12

 Times Cited Count:9 Percentile:55.32(Materials Science, Multidisciplinary)

295 (Records 1-20 displayed on this page)