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Journal Articles

Hyperfine splitting and nuclear spin polarization in NdPd$$_5$$Al$$_2$$ and Nd$$_3$$Pd$$_{20}$$Ge$$_6$$

Metoki, Naoto; Shibata, Kaoru; Matsuura, Masato*; Kitazawa, Hideaki*; Suzuki, Hiroyuki*; Yamauchi, Hiroki; Hagihara, Masato; Frontzek, M. D.*; Matsuda, Masaaki*

Journal of the Physical Society of Japan, 91(5), p.054710_1 - 054710_6, 2022/05

 Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)

Hyperfine splitting of Nd nuclei in NdPd$$_5$$Al$$_2$$ has been studied by means of high-resolution neutron spectroscopy. We observed inelastic peaks at $$hbaromega =pm3;{mu}$$eV coming from the hyperfine splitting in the magnetically ordered phase due to the hyperfine interactions between Nd nuclei ($$I$$=7/2) and the 4$$f$$ electrons with $$Gamma_6$$ ground state composed of mainly $$|pm9/2rangle$$. At very low temperatures, nuclear spin of Nd is polarized with increasing occupation probability of low energy levels and contributes to the enhancement of the antiferromagnetic Bragg intensities: the elastic non-spin-flip channel is dominant. As an application of this phenomenon, we determined the Nd moment and hyperfine splitting from the temperature dependence of an antiferromagnetic Bragg intensities for Nd$$_3$$Pd$$_{20}$$Ge$$_6$$.

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

 Times Cited Count:22 Percentile:80.37(Materials Science, Multidisciplinary)

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

Nature of structural instabilities in superconducting Sr$$_3$$Ir$$_4$$Sn$$_{13}$$

Kaneko, Koji; Cheung, Y. W.*; Hu, Y.*; Imai, Masaki*; Tanioku, Yasuaki*; Kanagawa, Hibiki*; Murakawa, Joichi*; Moriyama, Kodai*; Zhang, W.*; Lai, K. T.*; et al.

JPS Conference Proceedings (Internet), 30, p.011032_1 - 011032_6, 2020/03

Journal Articles

The $$f$$-electron state of the heavy fermion superconductor NpPd$$_5$$Al$$_2$$ and the isostructural family

Metoki, Naoto; Aczel, A. A.*; Aoki, Dai*; Chi, S.*; Fernandez-Baca, J. A.*; Griveau, J.-C.*; Hagihara, Masato*; Hong, T.*; Haga, Yoshinori; Ikeuchi, Kazuhiko*; et al.

JPS Conference Proceedings (Internet), 30, p.011123_1 - 011123_6, 2020/03

Rare earths (4$$f$$) and actinides (5$$f$$) provide variety of interesting states realized with competing interactions between the increasing number of $$f$$ electrons. Since crystal field splitting of many-body $$f$$ electron system is smaller than the bandwidth, (1) high resolution experiments are needed, (2) essentially no clear spectrum with well defined peaks is expected in itinerant Ce and U compounds, and (3) Np and Pu is strictly regulated. Therefore, systematic research on magnetic excitations by neutron scattering experiments of localized compounds and rare earth iso-structural reference is useful. We describe the $$f$$ electron states of heavy electron compounds NpPd$$_5$$Al$$_2$$ and actinide and rare earth based iso-structural family.

Journal Articles

Coexistence of ferromagnetic and stripe-type antiferromagnetic spin fluctuations in YFe$$_{2}$$Ge$$_{2}$$

Wo, H.*; Wang, Q.*; Shen, Y.*; Zhang, X.*; Hao, Y.*; Feng, Y.*; Shen, S.*; He, Z.*; Pan, B.*; Wang, W.*; et al.

Physical Review Letters, 122(21), p.217003_1 - 217003_5, 2019/05

 Times Cited Count:5 Percentile:41.86(Physics, Multidisciplinary)

Journal Articles

New precise measurements of muonium hyperfine structure at J-PARC MUSE

Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.

EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01

 Times Cited Count:13 Percentile:98.93(Quantum Science & Technology)

Journal Articles

Unique helical magnetic order and field-induced phase in trillium lattice antiferromagnet EuPtSi

Kaneko, Koji; Frontzek, M. D.*; Matsuda, Masaaki*; Nakao, Akiko*; Munakata, Koji*; Ohara, Takashi; Kakihana, Masashi*; Haga, Yoshinori; Hedo, Masato*; Nakama, Takao*; et al.

Journal of the Physical Society of Japan, 88, p.013702_1 - 013702_5, 2019/01

 Times Cited Count:61 Percentile:94.74(Physics, Multidisciplinary)

Journal Articles

Localized 5$$f^2$$ states in UPd$$_5$$Al$$_2$$ and valence crossover in the Vicinity of Heavy-Fermion superconductivity

Metoki, Naoto; Haga, Yoshinori; Yamamoto, Etsuji; Matsuda, Masaaki*

Journal of the Physical Society of Japan, 87(11), p.114712_1 - 114712_9, 2018/11

 Times Cited Count:3 Percentile:28.76(Physics, Multidisciplinary)

The localized 5$$f$$ states with 5$$f^2$$ ($$^3H_4$$) configuration of U$$^{4+}$$ ion have been revealed in UPd$$_5$$Al$$_2$$. We found that the low-lying states are the same as PrPd$$_5$$Al$$_2$$ flat orbitals with large $$J_z$$ are stabilized by a two-dimensional CEF potential in the unique crystal structure. The present study involves the valence crossover from tetravalent to trivalent in a series of AnPd$$_5$$Al$$_2$$, demonstrated by lattice and/or transport anomaly as well as many body effects in the vicinity of the boundary. The valence instability plays important role for the unusual heavy fermion superconductivity in NpPd$$_5$$Al$$_2$$.

Journal Articles

$$f$$-electron states in PrPd$$_5$$Al$$_2$$

Metoki, Naoto; Yamauchi, Hiroki; Suzuki, Hiroyuki*; Kitazawa, Hideaki*; Hagihara, Masato*; Masuda, Takatsugu*; Aczel, A. A.*; Chi, S.*; Hong, T.*; Matsuda, Masaaki*; et al.

Journal of the Physical Society of Japan, 87(9), p.094704_1 - 094704_8, 2018/09

 Times Cited Count:6 Percentile:46.04(Physics, Multidisciplinary)

The $$f$$-electron states of PrPd$$_5$$Al$$_2$$ were revealed by neutron inelastic scattering. The flat $$f$$-orbitals with large $$J_z$$ become stable under the two-dimensional CEF potential of unique crystal structure, which is the origin of the Ising anisotropy. A systematic understanding is possible in RPd$$_5$$Al$$_2$$ based on this CEF potential. Especially the $$XY$$-type anisotropy in NpPd$$_5$$Al$$_2$$ can be qualitatively understood with the positive Stevens factors. It mean that the local property is important for the physical properties of RPd$$_5$$Al$$_2$$ including the heavy fermion superconductivity in NpPd$$_5$$Al$$_2$$.

Journal Articles

Polarized neutron scattering study of the multiple order parameter system NdB$$_4$$

Metoki, Naoto; Yamauchi, Hiroki; Matsuda, Masaaki*; Fernandez-Baca, J. A.*; Watanuki, Ryuta*; Hagihara, Masato*

Physical Review B, 97(17), p.174416_1 - 174416_10, 2018/05

 Times Cited Count:7 Percentile:33.97(Materials Science, Multidisciplinary)

Neutron polarization analysis has been carried out in order to clarify the magnetic structure of multiple order parameter $$f$$-electron system NdB$$_4$$. We confirmed the non-collinear "all-in all-out" structure ($$Gamma$$$$_{4}$$) of the in-plane moment. We found that the magnetic moment along the $$c$$-axis $$m_c$$ showed diagonally antiferromagnetic structure ($$Gamma_{10}$$). The unusual magnetic ordering is phenomenologically understood via Landau theory. We also found that a long-period incommensurate modulation of the ($$0,0,1/2$$) antiferromagnetic structure of $$m_c$$ with the propagation $$q_{s1}$$ = (0.14, 0.14, 0.1) and $$q_{s2}$$ = (0.2, 0, 0.1) in phase III and IV, respectively. It is clear that the multipole degree-of-freedom based on pseudo-quartet $$f$$-electron state play important role.

Journal Articles

Measurements and analyses of the distribution of the radioactivity induced by the secondary neutrons produced by 17-MeV protons in compact cyclotron facility

Matsuda, Norihiro; Izumi, Yuichi*; Yamanaka, Yoshiyuki*; Gando, Toshiyuki*; Yamada, Masaaki*; Oishi, Koji*

EPJ Web of Conferences, 153, p.07001_1 - 07001_6, 2017/09

 Times Cited Count:0 Percentile:0.03(Nuclear Science & Technology)

Journal Articles

Measurement of aluminum activation cross section and gas production cross section for 0.4 and 3-GeV protons

Meigo, Shinichiro; Nishikawa, Masaaki; Iwamoto, Hiroki; Matsuda, Hiroki

EPJ Web of Conferences, 146, p.11039_1 - 11039_4, 2017/09

BB2016-1181.pdf:0.4MB

 Times Cited Count:2 Percentile:77.79(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Magnetic structure and dispersion relation of the $$S$$=1/2 quasi-one-dimensional Ising-like antiferromagnet BaCo$$_{2}$$V$$_{2}$$O$$_{8}$$ in a transverse magnetic field

Matsuda, Masaaki*; Onishi, Hiroaki; Okutani, Akira*; Ma, J.*; Agrawal, H.*; Hong, T.*; Pajerowski, D. M.*; Copley, J. R. D.*; Okunishi, Koichi*; Mori, Michiyasu; et al.

Physical Review B, 96(2), p.024439_1 - 024439_8, 2017/07

 Times Cited Count:12 Percentile:50.86(Materials Science, Multidisciplinary)

Journal Articles

Neutron powder diffraction study on the magnetic structure of NdPd$$_5$$Al$$_2$$

Metoki, Naoto; Yamauchi, Hiroki; Kitazawa, Hideaki*; Suzuki, Hiroyuki*; Hagihara, Masato*; Frontzek, M. D.*; Matsuda, Masaaki*; Fernandez-Baca, J. A.*

Journal of the Physical Society of Japan, 86(3), p.034710_1 - 034710_5, 2017/03

 Times Cited Count:9 Percentile:56.46(Physics, Multidisciplinary)

Magnetic structure of NdPd$$_5$$Al$$_2$$ has been studied by means of neutron powder diffraction. We observed remarkable magnetic reflections with the modulation vector $$q$$= (1/2 0 0) below the ordering temperature $$T_{rm N}$$ = 1.2 K. We found a collinear magnetic structure of Nd moment of 2.9(1) $${mu}_{rm B}$$ at 0.3 K parallel to the $$c$$-axis, where the ferromagnetically ordered $$a$$ planes stack with four Nd layer period of ++-- sequence along the $$a$$ direction with the distance between adjuscent Nd layers to be $$a/2$$. This is very similar to CePd$$_5$$Al$$_2$$ with $$q$$ = (0.23 0.23 0) and the Ce moment parallel to the $$c$$-axis. These structures with in-plane modulation $$q_{|}$$ is a consequence of the two dimensional nature of fermi surface topology in this family, coming from unique crystal structure with very long tetragonal unit cell and large distance $$>$$ 7${AA}$ between the rare earth layers separated by Al and two Pd layers.

Journal Articles

Melting of Pb charge glass and simultaneous Pb-Cr charge transfer in PbCrO$$_{3}$$ as the origin of volume collapse

Yu, R.*; Hojo, Hajime*; Watanuki, Tetsu; Mizumaki, Masaichiro*; Mizokawa, Takashi*; Oka, Kengo*; Kim, H.*; Machida, Akihiko; Sakaki, Koji*; Nakamura, Yumiko*; et al.

Journal of the American Chemical Society, 137(39), p.12719 - 12728, 2015/10

 Times Cited Count:34 Percentile:69.76(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Influence of electron doping on magnetic order in CeRu$$_2$$Al$$_{10}$$

Kobayashi, Riki*; Kaneko, Koji; Saito, Kotaro*; Mignot, J.-M.*; Andr$'e$, G.*; Robert, J.*; Wakimoto, Shuichi; Matsuda, Masaaki*; Chi, S.*; Haga, Yoshinori; et al.

Journal of the Physical Society of Japan, 83(10), p.104707_1 - 104707_5, 2014/10

 Times Cited Count:17 Percentile:69.54(Physics, Multidisciplinary)

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:44.92(Physics, Condensed Matter)

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:10 Percentile:41.83(Materials Science, Multidisciplinary)

Journal Articles

Effect of spin dilution on the magnetic state of delafossite CuCrO$$_{2}$$ with an $$S$$ = 3/2 antiferromagnetic triangular sublattice

Okuda, Tetsuji*; Uto, Kazuma*; Seki, Shinichiro*; Onose, Yoshinori*; Tokura, Yoshinori*; Kajimoto, Ryoichi; Matsuda, Masaaki*

Journal of the Physical Society of Japan, 80(1), p.014711_1 - 014711_7, 2011/04

 Times Cited Count:26 Percentile:76.10(Physics, Multidisciplinary)

Journal Articles

Anomalous low-field diamagnetic response in ultraclean URu$$_2$$Si$$_2$$ superconductor

Okazaki, Ryuji*; Shimozawa, Masaaki*; Shishido, Hiroaki*; Konczykowski, M.*; Haga, Yoshinori; Matsuda, Tatsuma; Yamamoto, Etsuji; Onuki, Yoshichika; Yanase, Yoichi*; Shibauchi, Takasada*; et al.

Journal of Physics; Conference Series, 273, p.012081_1 - 012081_4, 2011/02

 Times Cited Count:3 Percentile:62.53(Physics, Condensed Matter)

174 (Records 1-20 displayed on this page)