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Suzuki, Shintaro*; Takubo, Ko*; Kuga, Kentaro*; Higemoto, Wataru; Ito, Takashi; Tomita, Takahiro*; Shimura, Yasumichi*; Matsumoto, Yosuke*; Bareille, C.*; Wadachi, Hiroki*; et al.
Physical Review Research (Internet), 3(2), p.023140_1 - 023140_12, 2021/05
We report our experimental discovery of the transition temperature reaching 20 K in a Yb-based compound at ambient pressure. The Mn substitution at the Al site in an intermediate valence state of 
-YbAlB
not only induces antiferromagnetic transition at a record high temperature of 20 K but also transforms the heavy-fermion liquid state in -YbAlB into a highly resistive metallic state proximate to a Kondo insulator.
-YbAlB at high magnetic fieldsTerashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.
Journal of the Physical Society of Japan, 84(11), p.114715_1 - 114715_4, 2015/11
Times Cited Count：4 Percentile：34.89(Physics, Multidisciplinary)
Pr nuclear spin dynamics associated with antiferroquadrupolar order in PrV
Al
Ito, Takashi; Higemoto, Wataru; Sakai, Akito*; Nakatsuji, Satoru*; Tsujimoto, Masaki*
Physical Review B, 92(12), p.125151_1 - 125151_5, 2015/09
Times Cited Count：5 Percentile：23.78(Materials Science, Multidisciplinary)Uematsu, Daisuke*; Sagayama, Hajime*; Arima, Takahisa*; Ishikawa, Jun*; Nakatsuji, Satoru*; Takagi, Hidenori*; Yoshida, Masahiro*; Mizuki, Junichiro; Ishii, Kenji
Physical Review B, 92(9), p.094405_1 - 094405_6, 2015/09
Times Cited Count：22 Percentile：66.77(Materials Science, Multidisciplinary)-YbAl
Fe
B (
) at low temperatures and high magnetic fieldsTerashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.
Journal of Physics; Conference Series, 592(1), p.012020_1 - 012020_6, 2015/03
Times Cited Count：1 Percentile：43.19(Physics, Atomic, Molecular & Chemical)Valence fluctuation phenomena in rare-earth intermetallic compounds have attracted attention because the quantum criticality of the valence transition has been proposed theoretically. Recently, it was found that 
-YbAlB shows quantum criticality without tuning and has a strong mixed-valence state. In this study, we measured the magnetization curve and X-ray magnetoabsorption in -YbAlFeB (), which is a locally isostructural polymorph of -YbAlB. The magnetization and X-ray experiments were performed in fields up to 55 and 40 T, respectively. A small increase in the Yb valence was observed at fields where the magnetization curve exhibited a change in slope.
-
hybridization effect in PrTiAl and PrVAlTokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Sakai, Akito*; Nakatsuji, Satoru*; Harima, Hisatomo*
Physical Review B, 88(8), p.085124_1 - 085124_7, 2013/08
Times Cited Count：30 Percentile：75.39(Materials Science, Multidisciplinary)By means of 
Al NMR studies, we have investigated magnetic excitations and the hybridization effect between Pr 4 and conduction electrons in a pair of cubic compounds Pr
Al (=Ti, V). From Knight shift measurements we have evaluated comparative strengths for the - hybridization effect in these compounds and confirm a definite increase of hybridization on replacing Ti with V. Analysis of the spin-lattice relaxation rate 
reveals that the spectral width of magnetic fluctuations in crystalline electric field excited states is strongly temperature dependent. This result indicates that magnetic fluctuations are dominated by the strong - exchange coupling at high temperatures and thus is nicely consistent with the Kondo picture that features ln
dependence of resistivity over the same temperature region.
- and -TbAlB at low temperature and high magnetic fieldsMatsuda, Yasuhiro*; Nakamura, Toshiyuki*; Kuga, Kentaro*; Nakatsuji, Satoru*; Michimura, Shinji*; Inami, Toshiya; Kawamura, Naomi*; Mizumaki, Masaichiro*
Journal of the Korean Physical Society, 62(12), p.1778 - 1781, 2013/06
Times Cited Count：10 Percentile：55.98(Physics, Multidisciplinary)The valence state of Yb ions in - and -YbAlB has been investigated by X-ray absorption and emission spectroscopy at temperatures from 2 to 280 K. It is found that the valence gradually increases with increasing temperature toward 3+ and that the characteristic temperature of the valence fluctuations is about 290 K. We also observe a small increase in the Yb valence (
0.002) in -YbAlB by a magnetic field of 32 T at 40 K.
ground quartet systems Sm
Al (: Ti, V, Cr)Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Sakai, Akito*; Nakatsuji, Satoru*
Journal of the Physical Society of Japan, 81(Suppl.B), p.SB050_1 - SB050_4, 2012/12
Recently, 
Al compounds (
: rare earth, : transition metal) have attracted much attention due to interesting physical properties closely related to their caged-structure. Each ion is confined in a Frank-Kasper cage consisting of 16 Al atoms and the large coordination number leads to strong - hybridization. In addition, the Frank-Kasper cage allows various multipole degrees of freedom for the -electrons at low because of a highly symmetric crystalline-electric-field (CEF). Among the Al series, Pr
Al (: Ti, V) and SmAl (: Ti, V, Cr) exhibit both these features. The 
ground doublet systems PrAl (: Ti, V) show a phase transition at 
= 2.0K (Ti) and 0.6K (V). The order parameter is believed to be an electric quadrupole active in the subspace. A possibility of the quadrupole Kondo effect has been discussed based on characteristic -dependence in specific heat, resistivity, and magnetic susceptibility. The 
ground quartet systems SmAl (: Ti, V, Cr) also exhibit a phase transition at = 6.4K (Ti), 2.3K (V), and 1.8K (Cr). A nuclear specific heat study in SmTiAl suggests that the primary order parameter is a magnetic dipole in spite of field-insensitive nature of the phase boundary. A possible importance of a secondarily ordered octupole moment was discussed. We here present a microscopic study of PrTiAl and SmAl (: Ti, V, Cr) using muon spin relaxation. In PrTiAl, no additional local field was observed in the ordered phase. This strongly supports the quadrupole ordering scenario. On the other hand, an appearance of a coherent local field was observed below in SmAl. This is consistent with the primary magnetic dipole ordering. The frequency distribution suggests that the magnetic structure is possibly different between the SmAl compounds.
Nakatsuji, Satoru*; Kuga, Kentaro*; Kimura, Kenta*; Satake, Ryuta*; Katayama, Naoyuki*; Nishibori, Eiji*; Sawa, Hiroshi*; Ishii, Rieko*; Hagiwara, Masayuki*; Bridges, F.*; et al.
Science, 336(6081), p.559 - 563, 2012/05
Times Cited Count：114 Percentile：95.24(Multidisciplinary Sciences)Frustrated magnetic materials can remain disordered to the lowest temperatures. Such is the case for Ba
CuSbO
, which is magnetically anisotropic at the atomic scale but curiously isotropic on mesoscopic length and time scales. We find that the frustration on the triangular lattice is imprinted in a nanostructured honeycomb lattice of Cu
ions that resists a coherent static Jahn-Teller distortion. The resulting two-dimensional random-bond spin-1/2 system on the honeycomb lattice has a broad spectrum of spin-dimer like excitations and low-energy spin degrees of freedom that retain.
SR evidence of nonmagnetic order and Pr hyperfine-enhanced nuclear magnetism in the cubic ground doublet system PrTiAlIto, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Luetkens, H.*; Baines, C.*; Sakai, Akito*; Nakatsuji, Satoru*
Journal of the Physical Society of Japan, 80(11), p.113703_1 - 113703_4, 2011/11
Times Cited Count：30 Percentile：78.75(Physics, Multidisciplinary)AlTokunaga, Yo; Sakai, Hironori; Saito, Yo; Kambe, Shinsaku; Sakai, Akito*; Nakatsuji, Satoru*
no journal, ,
no abstracts in English
SR studies of 
Al (: Pr, Sm, : Ti, V, Cr) with a cage structureIto, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Sakai, Akito*; Nakatsuji, Satoru*
no journal, ,
no abstracts in English
SR study of PrTiAlIto, Takashi; Higemoto, Wataru; Sakai, Akito*; Nakatsuji, Satoru*
no journal, ,
no abstracts in English
AlTokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Sakai, Akito*; Nakatsuji, Satoru*
no journal, ,
no abstracts in English
Al, 2Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Sakai, Akito*; Nakatsuji, Satoru*
no journal, ,
no abstracts in English
Al (=Ti, V)Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Sakai, Akito*; Nakatsuji, Satoru*
no journal, ,
In this study, we have performed Al NMR/NQR measurements for PrAl (=Ti, V). Al NMR spectra have been measured in a temperature range between 1.4 and 300 K, and the temperature dependence of the Knight shift 
has been extracted for Al(2) and Al(3). Then, from the so-called vs 
plot, the hyperfine coupling constants (
) has been estimated for each site in each compound. A large obtained for Al(3) indicates the strong hybridization between Pr and Al-cage. In addition, the stronger hybridization in PrVAl than in PrTiAl is confirmed from the values.
S (A = Cd, Mg) probed by SRHigemoto, Wataru; Ito, Takashi; Koda, Akihiro*; Iritani, Kenshi*; Halim, M.*; Nakatsuji, Satoru*
no journal, ,
Varieties of magnetic states are seen in spinel structural magnets due to spin frustration effect. In particular, much attention is paid on recent study on pyrochlore structural magnet with rare-earth elements because interesting spin state, spin ice or other state, is observed. We have studied on spinel magnet AYbS to clarify the magnetic ground state by means of muon spin relaxation method. In our measurement, static magnetic ordering state was clearly observed.
Se (A=Cd, Mg) probed by SRHigemoto, Wataru; Ito, Takashi; Iritani, Kenshi*; Halim, M.*; Nakatsuji, Satoru*
no journal, ,
A spinel structural system shows a variety of the magnetic state due to its frustration effect. Up to now, we have studied the magnetic ground state of spinel structural system AYbS(A=Cd, Mg) by using muon spin relaxation method and observed the appearance of the magnetic ordering state below 2K in CdYbS and 1.5K in MgYbS. For systematic study of the frustration effect, we are measuring muon spin relaxation in same structural compounds AYbSe (A=Cd, Mg). In CdYbSe, the local magnetic field was observed below 2K. In the presentation, we will discuss the detail of the magnetic state.
AlIto, Takashi; Higemoto, Wataru; Sakai, Akito*; Nakatsuji, Satoru*
no journal, ,
no abstracts in English
