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Fe and 
Co nuclear magnetic resonance studiesSakai, Hironori; Hattori, Taisuke; Tokunaga, Yo; Kambe, Shinsaku; Ueda, Hiroaki*; Tanioku, Yasuaki*; Michioka, Chishiro*; Yoshimura, Kazuyoshi*; Takao, Kenta*; Shimoda, Aiko*; et al.
Physical Review B, 98(6), p.064403_1 - 064403_10, 2018/08
Times Cited Count：10 Percentile：45.99(Materials Science, Multidisciplinary)To specify preferential occupation sites of Co substituents and to clarify charge and spin states of Co ions in (La, Co)-cosubstituted hexagonal magnetoplumbite-type (M-type) Sr ferrite, Fe and Co nuclear magnetic resonance (NMR) spectra are measured under zero and external magnetic fields using powdered and single crystalline specimens. To a considerable degree, the charge compensation between La
and Co
works in the equal (La, Co)-codoped case, where more than half of the Co ions are considered to be present in the minority spin 
sites at the center of the oxygen tetrahedra, with the 
= 3/2 state carrying a small orbital moment owing to spin-orbit interaction. The remaining small number of high-spin Co ( = 3/2, 
= 1) ions with unquenched orbital moments would be distributed to the other octahedral 
, 
, and 
sites.
Imai, Masaki; Michioka, Chishiro*; Ueda, Hiroaki*; Yoshimura, Kazuyoshi*
Physical Review B, 95(5), p.054417_1 - 054414_7, 2017/02
Times Cited Count：2 Percentile：11.52(Materials Science, Multidisciplinary)We took 
P NMR measurements of mainly paramagnetic phase to reveal the itinerant-electron metamagnetic transition, and of its magnetically ordered phase, and characterized their spin fluctuations by estimating the spin fluctuation parameter 
corresponding to the width of the spin fluctuation in the spectrum in frequency space. As 
increases from 0 to 0.5, the in-plane component of decreases proportionally with the metamagnetic transition field. In the antiferromagnetic cT phase, is constant and spin fluctuations show an isotropic character in contrast to their behavior in the paramagnetic ucT phase. These results indicate that the in-plane spin fluctuations due to the quasi-two-dimensional crystal structure play a significant role in the metamagnetic transition of this system.
O
Tomiyasu, Keisuke*; Iwasa, Kazuaki*; Ueda, Hiroaki*; Niitaka, Seiji*; Takagi, Hidenori*; Kawamura, Seiko; Kikuchi, Tatsuya; Inamura, Yasuhiro; Nakajima, Kenji; Yamada, Kazuyoshi*
Physical Review Letters, 113(23), p.236402_1 - 236402_5, 2014/12
Times Cited Count：16 Percentile：68.53(Physics, Multidisciplinary)Spin fluctuations were studied over a wide momentum (
) and energy (
) space in the frustrated 
-electron heavy-fermion metal LiVO by time-of-flight inelastic neutron scattering. We observed the overall 
evolutions near the characteristic 
= 0.6 
peak and found another weak broad magnetic peak around 2.4 . The data are described by a simple response function, a partially delocalized magnetic form factor, and antiferromagnetic short-range spatial correlations, indicating that heavy-fermion formation is attributable to spin-orbit fluctuations with orbital hybridization.
Matsuda, Masaaki; Oyama, Kenji*; Yoshii, Shunsuke*; Nojiri, Hiroyuki*; Frings, P.*; Duc, F.*; Vignolle, B.*; Rikken, G. L. J. A.*; Regnault, L.-P.*; Lee, S.-H.*; et al.
Physical Review Letters, 104(4), p.047201_1 - 047201_4, 2010/01
Times Cited Count：28 Percentile：77.3(Physics, Multidisciplinary)OMatsuda, Masaaki; Ueda, Hiroaki*; Kikkawa, Akiko*; Tanaka, Yoshikazu*; Katsumata, Koichi*; Narumi, Yasuo*; Inami, Toshiya; Ueda, Yutaka*; Lee, S.-H.*
Nature Physics, 3(6), p.397 - 400, 2007/06
Times Cited Count：104 Percentile：93.31(Physics, Multidisciplinary)Cr-CrCr-based spinel compounds ACrO (A=Mg, Zn, Cd, and Hg) are so far the best model systems for a network of corner-sharing tetrahedrons with isotropic nearest-neighbor antiferromagnetic interactions. The systems exhibit novel spin-Peierls phase transitions from cubic spin liquid to non-cubic N
el states at low temperatures. Recent bulk magnetization studies on CdCrO and HgCrO revealed the magnetic field-induced half magnetization plateau states that are stable over a wide range of field. Recent bulk magnetization studies on CdCrO and HgCrO revealed the magnetic field-induced half magnetization plateau states that are stable over a wide range of field.
O
Matsuda, Masaaki; Takeda, Masayasu; Nakamura, Mitsutaka; Kakurai, Kazuhisa; Osawa, Akira*; Leli
vre-Berna, E.*; Chung, J.-H.*; Ueda, Hiroaki*; Takagi, Hidenori*; Lee, S.-H.*
Physical Review B, 75(10), p.104415_1 - 104415_6, 2007/03
Times Cited Count：43 Percentile：81.73(Materials Science, Multidisciplinary)A frustrated spinel CdCrO undergoes a three-dimensional spin-Peierls transition at 
= 7.8 K from a cubic paramagnetic to a tetragonal Nel state. The Nel state has a spiral magnetic structure with a characteristic wave vector of 
when the 
axis elongated. Here we report our spherical neutron polarimetry experiments to investigate the spiral spin structure in detail. Our results indicate that the spins lie in the 
plane perpendicular to the direction of the spiral modulation. We also found that the spiral structure in the plane is elliptical with the -component larger by 
24% than the 
-component, suggesting a strong coupling between the magnetic structure and structural distortion. Unpolarized neutron diffraction under an external magnetic field has also been performed. The magnetic field dependence suggests existence of magnetic anisotropy in the Nel state, which is consistent with our previous inelastic studies.
O using an X-ray diffraction techniqueInami, Toshiya; Owada, Kenji; Tsubota, Masami; Murata, Yuto*; Matsuda, Yasuhiro*; Nojiri, Hiroyuki*; Ueda, Hiroaki*; Murakami, Yoichi*
Journal of Physics; Conference Series, 51, p.502 - 505, 2006/00
Times Cited Count：16 Percentile：97.58(Physics, Condensed Matter)no abstracts in English
OChung, J.-H.*; Matsuda, Masaaki; Lee, S.-H.*; Kakurai, Kazuhisa; Ueda, Hiroaki*; Sato, Taku*; Takagi, Hidenori*; Hong, K.-P.*; Park, S.*
Physical Review Letters, 95(24), p.247204_1 - 247204_4, 2005/12
Times Cited Count：140 Percentile：95.25(Physics, Multidisciplinary)no abstracts in English
O studied by polarized neutron techniquesMatsuda, Masaaki; Osawa, Akira*; Takeda, Masayasu; Kakurai, Kazuhisa; Chung, J.-H.*; Lee, S.-H.*; Ueda, Hiroaki*; Takagi, Hidenori*
no journal, ,
CdCrO has the spinel structure, in which geometrical frustration exists between the Cr moments located at the corners of the tetrahedron. It shows an incommensurate antiferromagnetic ordering below 
=7.8K with a characteristic wave vector of 
(
). We first performed a 1D polarized neutron analysis and determined that the Cr moments has a planer anisotropy in the plane, indicating that the magnetic structure is spiral. Finally, the 3D polarized neutron analysis using a CRYOPAD on TAS-1 at JRR-3 determined that the magnetic structure is elliptical spiral in the plane with ellipsoid slightly elongated along the axis. The origin of the structure will be discussed.
O studied by polarized neutron techniquesMatsuda, Masaaki; Osawa, Akira*; Takeda, Masayasu; Nakamura, Mitsutaka; Lelivre-Berna, E.*; Kakurai, Kazuhisa; Chung, J.-H.*; Lee, S.-H.*; Ueda, Hiroaki*; Takagi, Hidenori*
no journal, ,
no abstracts in English
OMatsuda, Masaaki; Osawa, Akira*; Takeda, Masayasu; Nakamura, Mitsutaka; Kakurai, Kazuhisa; Lelivre-Berna, E.*; Chung, J.-H.*; Lee, S.-H.*; Ueda, Hiroaki*; Takagi, Hidenori*
no journal, ,
no abstracts in English
O in high magnetic fieldMatsuda, Masaaki; Ueda, Hiroaki*; Kikkawa, Akiko*; Tanaka, Yoshikazu*; Katsumata, Koichi*; Narumi, Yasuo*; Inami, Toshiya; Ueda, Yutaka*; Lee, S.-H.*
no journal, ,
no abstracts in English
OInami, Toshiya; Owada, Kenji; Tsubota, Masami; Matsuda, Yasuhiro*; Nojiri, Hiroyuki*; Ueda, Hiroaki*
no journal, ,
no abstracts in English
Matsuda, Masaaki; Honda, Zentaro*; Katori, Hiroko*; Takagi, Hidenori*; Ueda, Hiroaki*; Ueda, Yutaka*; Mitamura, Hiroyuki*; Kindo, Koichi*
no journal, ,
O in pulsed high magnetic fieldMatsuda, Masaaki; Oyama, Kenji*; Yoshii, Shunsuke*; Nojiri, Hiroyuki*; Ueda, Hiroaki*; Ueda, Yutaka*; Regnault, L.-P.*; Vignole, B.*; Duc, F.*; Frings, P.*; et al.
no journal, ,
no abstracts in English
O in pulsed high magnetic fieldMatsuda, Masaaki; Oyama, Kenji*; Yoshii, Shunsuke*; Nojiri, Hiroyuki*; Ueda, Hiroaki*; Ueda, Yutaka*; Regnault, L.-P.*; Vignole, B.*; Duc, F.*; Frings, P.*; et al.
no journal, ,
no abstracts in English
Matsuda, Masaaki; Oyama, Kenji*; Yoshii, Shunsuke*; Nojiri, Hiroyuki*; Frings, P.*; Duc, F.*; Vignole, B.*; Rikken, G. L. J. A.*; Regnault, L.-P.*; Lee, S.-H.*; et al.
no journal, ,
