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Al
and Nd
Pd
Ge
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 NdPdAl has been studied by means of high-resolution neutron spectroscopy. We observed inelastic peaks at 
eV coming from the hyperfine splitting in the magnetically ordered phase due to the hyperfine interactions between Nd nuclei (
=7/2) and the 4
electrons with 
ground state composed of mainly 
. 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 NdPdGe.
Arai, Yosuke*; Kuroda, Kenta*; Nomoto, Takuya*; Tin, Z. H.*; Sakuragi, Shunsuke*; Bareille, C.*; Akebi, Shuntaro*; Kurokawa, Kifu*; Kinoshita, Yuto*; Zhang, W.-L.*; et al.
Nature Materials, 21(4), p.410 - 415, 2022/04
Times Cited Count：11 Percentile：78.54(Chemistry, Physical)Kuroda, Kenta*; Arai, Yosuke*; Rezaei, N.*; Kunisada, So*; Sakuragi, Shunsuke*; Alaei, M.*; Kinoshita, Yuto*; Bareille, C.*; Noguchi, Ryo*; Nakayama, Mitsuhiro*; et al.
Nature Communications (Internet), 11, p.2888_1 - 2888_9, 2020/06
Times Cited Count：26 Percentile：76.75(Multidisciplinary Sciences)-electron state of the heavy fermion superconductor NpPdAl and the isostructural familyMetoki, 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) and actinides (5) provide variety of interesting states realized with competing interactions between the increasing number of electrons. Since crystal field splitting of many-body 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 electron states of heavy electron compounds NpPdAl and actinide and rare earth based iso-structural family.
-electron states in PrPdAlMetoki, 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：44.60(Physics, Multidisciplinary)The -electron states of PrPdAl were revealed by neutron inelastic scattering. The flat -orbitals with large 
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 RPdAl based on this CEF potential. Especially the 
-type anisotropy in NpPdAl can be qualitatively understood with the positive Stevens factors. It mean that the local property is important for the physical properties of RPdAl including the heavy fermion superconductivity in NpPdAl.
-electron states in NdPdAlMetoki, Naoto; Yamauchi, Hiroki; Suzuki, Hiroyuki*; Kitazawa, Hideaki*; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro
Journal of the Physical Society of Japan, 87(8), p.084708_1 - 084708_7, 2018/08
Times Cited Count：6 Percentile：44.60(Physics, Multidisciplinary)Inelastic neutron scattering experiments were carried out in order to study the -electron states of NdPdAlThe CEF levels at 0K, 35.4K, 88.3K, 101.5K, and 198.8K were clarified from the excitation spectra. The ground state contains the orbital with 
as a main component due to a large negative B
K, which is the origin of the strong uniaxial anisotropy. The estimated magnetic moment, the calculated susceptibility, magnetization curve, and specific heat are in good agreement with the experimental data. The existence of a common charge distribution with CePdAl and PrPdAl. Indicates that a localized character is important even in actinide-based iso-structural compounds as actually observed in UPdAl and also NpPdAl, in which the valence crossover plays important role for the heavy fermion superconductivity.
Kuroda, Kenta*; Ochi, Masayuki*; Suzuki, Hiroyuki*; Hirayama, Motoaki*; Nakayama, Mitsuhiro*; Noguchi, Ryo*; Bareille, C.*; Akebi, Shuntaro*; Kunisada, So*; Muro, Takayuki*; et al.
Physical Review Letters, 120(8), p.086402_1 - 086402_6, 2018/02
Times Cited Count：55 Percentile：91.23(Physics, Multidisciplinary)AlMetoki, 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：55.28(Physics, Multidisciplinary)Magnetic structure of NdPdAl has been studied by means of neutron powder diffraction. We observed remarkable magnetic reflections with the modulation vector 
= (1/2 0 0) below the ordering temperature 
= 1.2 K. We found a collinear magnetic structure of Nd moment of 2.9(1) 
at 0.3 K parallel to the 
-axis, where the ferromagnetically ordered 
planes stack with four Nd layer period of ++-- sequence along the direction with the distance between adjuscent Nd layers to be 
. This is very similar to CePdAl with = (0.23 0.23 0) and the Ce moment parallel to the -axis. These structures with in-plane modulation 
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
between the rare earth layers separated by Al and two Pd layers.
Terada, Noriki*; Khalyavin, D. D.*; Manuel, P.*; Osakabe, Toyotaka; Kikkawa, Akiko*; Kitazawa, Hideaki*
Physical Review B, 93(8), p.081104_1 - 081104_5, 2016/02
Times Cited Count：18 Percentile：61.21(Materials Science, Multidisciplinary)We performed neutron diffraction experiments under high pressures and high magnetic fields using a single crystal of the multiferroic compound TbMnO in order to clarify the mechanism associated with pressure/magnetic-field-induced giant ferroelectric polarization. We found that the E-type ordering of Mn spins induces giant ferroelectric polarization over all the parameter regions investigated, through an exchange striction mechanism. Furthermore, we propose that the polarization is reduced by polar ordering of the Tb moments in a zero magnetic field and is enhanced via the field-induced transition from polar to nonpolar Tb orderings at 2T.
Mukai, Hiroki*; Hatta, Tamao*; Kitazawa, Hideaki*; Yamada, Hirohisa*; Yaita, Tsuyoshi; Kogure, Toshihiro*
Environmental Science & Technology, 48(22), p.13053 - 13059, 2014/12
Times Cited Count：116 Percentile：94.36(Engineering, Environmental)no abstracts in English
Terada, Noriki*; Khalyavin, D. D.*; Manuel, P.*; Osakabe, Toyotaka; Radaelli, P. G.*; Kitazawa, Hideaki*
Physical Review B, 89(22), p.220403_1 - 220403_6, 2014/06
Times Cited Count：30 Percentile：74.43(Materials Science, Multidisciplinary)We have studied the pressure effect on the magnetic orderings in the strongly frustrated antiferromagnet CuFeO, by using neutron diffraction experiments under hydrostatic pressure. The main result is elucidation of the pressure-temperature magnetic phase diagram, consisting of the fourmagnetic phases including two polar ones. In particular, in the 3 GPa 
P 4 GPa pressure range, the ICM2 phase with the proper screw magnetic ordering stabilized. This polar phase is almost identical to the ferroelectric incommensurate (FEIC) phase induced by either a magnetic field or chemical doping. Furthermore, above 4 GPa, a new low-symmetry phase ICM3 is realized. This is unique for the family of delafossite multiferroics and implies an admixture of both cycloidal and proper screw spin configurations. The sequence of the observed magnetic phases with changing pressure might be attributed to pressure suppression of the monoclinic lattice distortions responsible for releasing the spin frustration in the system.
Terada, Noriki*; Tsuchiya, Yoshinori*; Kitazawa, Hideaki*; Metoki, Naoto
Journal of the Korean Physical Society, 62(12), p.1905 - 1909, 2013/06
Times Cited Count：3 Percentile：26.73(Physics, Multidisciplinary)We have investigated magnetic and nonmagnetic impurity substitution effects on magnetic ordering of a frustrated isosceles triangular lattice antiferromagnet CuMnO by means of the magnetic neutron diffraction measurements on Cu(Mn
Ga
)O. While the magnetic wave vector of the magnetic ground state of "magnetically" substituted Cu(Mn
Cu
)O with x = 0:04 is Q = (-1/2 1/2 0), that in the "nonmagnetically" substituted Cu(MnGa)O with y =0.05, 0.15 and 0.20 is Q = (-1/2 1/2 1/2) that is identical to that of pure CuMnO. We discuss an influence of magnetic or nonmagnetic impurity substitution on the magnetic ordering of CuMnO, by comparing the results of Cu(MnGa)O with Cu(MnCux)O.
Ga
O (
= 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：13 Percentile：62.60(Physics, Multidisciplinary)GaO (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
Nigo, Seisuke*; Kubota, Masato; Harada, Yoshitomo*; Hirayama, Taisei*; Kato, Seiichi*; Kitazawa, Hideaki*; Kido, Giyu*
Journal of Applied Physics, 112(3), p.033711_1 - 033711_6, 2012/08
Times Cited Count：63 Percentile：89.41(Physics, Applied)P
O
Hase, Masashi*; D
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：44.66(Physics, Condensed Matter)We determined the magnetic structure below 
K of the spin-5/2 antiferromagnetic (AF) trimer substance SrMnPO using neutron powder diffraction experiments. The incommensurate propagation vector is expressed as [0, 
, 0], due to competition between the nearest-neighbor and next-nearest-neighbor interactions in trimerized chains. The value of is 0.316 to 0.331, changing rapidly at 
K. We confirmed that the intra-trimer 
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).
POHase, 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：40.86(Materials Science, Multidisciplinary)Terada, Noriki*; Tsuchiya, Yoshinori*; Kitazawa, Hideaki*; Osakabe, Toyotaka; Metoki, Naoto; Igawa, Naoki; Oyama, Kenji*
Physical Review B, 84(6), p.064432_1 - 064432_8, 2011/08
Times Cited Count：17 Percentile：56.85(Materials Science, Multidisciplinary)We have studied the magnetic correlations of the isosceles triangular lattice antiferromagnet CuMnO. Above 
, the magnetic correlations are characterized by a two-dimensional (2D) short-range correlation. Below , the magnetic structures have been identified to be collinear with the magnetic moments almost parallel to the 
orbitals. The stacking sequence along the direction is changed from antiferromagnetic to ferromagnetic by atomic disorder. We find that the second-nearest-neighbor interlayer interaction plays an important role for the magnetic stacking along the axis. The magnetic excitation below is characterized by collective spin-wave excitation with an energy gap of 6 meV from the three-dimensional long-range magnetic order and by spin-liquid-like 2D excitation, indicated by specific heat.
Terada, Noriki*; Osakabe, Toyotaka; Kitazawa, Hideaki*
Physical Review B, 83(2), p.020403_1 - 020403_4, 2011/01
Times Cited Count：12 Percentile：45.97(Materials Science, Multidisciplinary)We succeeded in observing pressure-suppressed magnetic long-range ordering (LRO) in the triangular-lattice antiferromagnet CuFeO, using neutron-diffraction experiments under an isotropic pressure. The magnetic LRO of the four-sublattice ground state under ambient pressure in CuFeO almost disappears at the high pressure of 7.9 GPa, and is replaced by an incommensurate order with temperature-independent wave number of (0.192 0.192 1.5). The incommensurate wave number observed at 7.9 GPa corresponds to that observed just above the temperature at which lattice distortion and magnetic LRO simultaneously occur under ambient pressure. Therefore, the long-range magnetic ordering disappears because the high pressure suppressed the lattice distortion that otherwise relieves spin frustration and leads the spin system to LRO.
AlInami, Toshiya; Terada, Noriki*; Kitazawa, Hideaki*; Sakai, Osamu*
Journal of Physics; Conference Series, 200, p.032022_1 - 032022_4, 2010/02
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)
