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Zn
Kitazawa, Takafumi
Hamon, 35(3), p.119 - 122, 2025/08
Ikeda, Yoichi*; Umemoto, Yoshihiko*; Matsumura, Daiju; Tsuji, Takuya; Hashimoto, Yuki*; Kitazawa, Takafumi*; Fujita, Masaki*
Materials Transactions, 64(9), p.2254 - 2260, 2023/09
Times Cited Count：4 Percentile：31.44(Materials Science, Multidisciplinary)ZnKitazawa, Takafumi; Ikeda, Yoichi*; Sakakibara, Toshiro*; Matsuo, Akira*; Shimizu, Yusei*; Tokunaga, Yo; Haga, Yoshinori; Kindo, Koichi*; Nambu, Yusuke*; Ikeuchi, Kazuhiko*; et al.
Physical Review B, 108(8), p.085105_1 - 085105_7, 2023/08
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)
Np-M
ssbauer and magnetic studyNakamura, Akio; Nakada, Masami; Nakamoto, Tadahiro*; Kitazawa, Takafumi*; Takeda, Masuo*
Journal of Alloys and Compounds, 444-445, p.621 - 633, 2007/10
Times Cited Count：3 Percentile：27.06(Chemistry, Physical)no abstracts in English
(C
H
O)(C
HN)Nakamura, Akio; Nakada, Masami; Nakamoto, Tadahiro*; Kitazawa, Takafumi*; Takeda, Masuo*
Journal of Magnetism and Magnetic Materials, 310(2, Part2), p.1447 - 1449, 2007/03
Magnetic property of a nitrogen (N)-coordinated neptunyl (+2) (Np(VI)) complex. 1 NpO(acac)(py) (acac=CHO, py=CHN) was studied by DC magnetization (M) measurements. While previous Np Mssbauer data of 1 exhibited para magnetic-relaxation spectra similar to other oxo-neptunyls (+1,+2), the DC-
data have revealed many strikingly different features of 1 from the latter: first, its reciprocal susceptibility (
) vs. 
(K) plots showed a peculiar strongly field (
)-dependent nonparamagnetic behavior, which suggests the presence of small ferromagnetic component with 
300 K. In addition, its low-temperature isothermal exhibited anomalous relaxation behavior involving initial over-responsive change and subs equent drift back to its "equilibrium" value (
). Moreover, such showed strong perturbation effect from the SQUID- measurement itself. Such novel magnetic features suggest the presence of a largely metastable fluctuating magnetic (spin plus orbital) state in 1 as a collective body of individual Ising-type neptunyl (O=Np=O)
molecular magnets.
Saeki, Masakatsu; Nakada, Masami; Kawasaki, Takeshi*; Nishimura, Tatsuru*; Kitazawa, Takafumi*; Takeda, Masuo*
Journal of Radioanalytical and Nuclear Chemistry, 270(2), p.379 - 384, 2006/11
Times Cited Count：3 Percentile：23.16(Chemistry, Analytical)no abstracts in English
(CHO)(CHN)Nakamura, Akio; Nakada, Masami; Nakamoto, Tadahiro*; Kitazawa, Takafumi*; Takeda, Masuo*
Journal of the Physical Society of Japan, 75(Suppl.), p.146 - 148, 2006/08
no abstracts in English
ssbauer Isomer shifts and Structures of Neptunium compoundsSaeki, Masakatsu; Nakada, Masami; Kitazawa, Takafumi*
KURRI-KR-106, p.38 - 42, 2004/03
no abstracts in English
-UO(OH)Nakada, Masami; Kitazawa, Takafumi*; Saito, Takashi*; Wang, J.*; Takeda, Masuo*; Yamashita, Toshiyuki; Saeki, Masakatsu
Bulletin of the Chemical Society of Japan, 76(7), p.1375 - 1378, 2003/07
Times Cited Count：6 Percentile：29.40(Chemistry, Multidisciplinary)no abstracts in English
Zn (Tr = Co, Rh, Ir)Kitazawa, Takafumi; Haga, Yoshinori; Sakai, Hironori; Tokiwa, Yoshifumi; Yamamoto, Etsuji; Kambe, Shinsaku; Tokunaga, Yo
no journal, ,
no abstracts in English
-UTe
Sakai, Hironori; Tabata, Chihiro; Kaneko, Koji; Kitazawa, Takafumi; Yamamoto, Etsuji; Tokiwa, Yoshifumi; Kambe, Shinsaku; Tokunaga, Yo; Haga, Yoshinori
no journal, ,
In this study, we successfully grew a single crystal of the uranium-based van der Waals compound -UTe. The crystal structure includes a Te-Te bilayer composed of Te(2) and Te(3) atoms. The U and Te(1) atoms are between the double Te layers. The shortest U-U distance exceeds the Hill limit of 
3.5 
electron system. The conduction properties within the 
-plane exhibit semiconducting behavior, and the magnetism demonstrates easy-plane anisotropy. An antiferromagnetic transition occurs at 
=5 K; however, the magnetic structure remains undetermined. We conducted neutron diffraction experiments to elucidate the magnetic structure and address this. This presentation will discuss this compound's fundamental physical and magnetic properties.
ZnKitazawa, Takafumi; Haga, Yoshinori
no journal, ,
no abstracts in English
ZnKitazawa, Takafumi; Ikeda, Yoichi*; Imajo, Shusaku*; Haga, Yoshinori; Kohama, Yoshimitsu*; Tokunaga, Yo; Fujita, Masaki*
no journal, ,
no abstracts in English
ZnKitazawa, Takafumi; Tokunaga, Yo; Haga, Yoshinori; Opletal, P.; Sakai, Hironori; Tokiwa, Yoshifumi; Yamamoto, Etsuji; Kambe, Shinsaku; Ikeda, Yoichi*; Fujita, Masaki*
no journal, ,
ZnKitazawa, Takafumi; Ikeda, Yoichi*; Matsuo, Akira*; Imajo, Shusaku*; Shimizu, Yusei*; Kawamata, Masahiro*; Tokunaga, Yo; Haga, Yoshinori; Opletal, P.; Sakai, Hironori; et al.
no journal, ,
A diluted Yb system (Lu,Yb)RhZn is an impurity Kondo alloy with quasi-octet degeneracy due to strong -
hybridization. In addition to the large degeneracy of 
, we found field-induced single-ion magnetic anisotropy above about 5 T, which cannot be explained by the existing Kondo model. To understand the -electron state under magnetic fields, where the magnetic anisotropy develops, we measured the magnetization and specific heat of the diluted Yb system (Lu,Yb)RhZn under pulsed high magnetic fields. The magnetization curves coincided between the processes of increasing and decreasing magnetic fields. This indicates that eddy-current heating is sufficiently suppressed, and isothermal magnetization curves can be measured. The magnetic easy and hard axes along the 
and 
directions, respectively, remained unchanged even above the Kondo crossover field of 22.7 T, where the -electrons are localized. The field dependence of the electronic specific heat coefficients, estimated from the specific heat measurements, increased to about 1 J Yb-mol K
and decreased around the Kondo crossover field. The decreasing electronic specific heat coefficients at the Kondo field suggest the localization of the -electrons. In addition, the anisotropic magnetic response was observed not only in magnetization but also in specific heat measurements.
Haga, Yoshinori; Tokiwa, Yoshifumi; Sakai, Hironori; Kitazawa, Takafumi; Yamamoto, Etsuji; Kambe, Shinsaku; Tokunaga, Yo; Ikarugi, Riko; Muro, Yuji*
no journal, ,
no abstracts in English
ZnKitazawa, Takafumi; Shimura, Yasuyuki*; Onimaru, Takahiro*; Haga, Yoshinori; Sakai, Hironori; Tokiwa, Yoshifumi; Kambe, Shinsaku; Yamamoto, Etsuji; Tokunaga, Yo
no journal, ,
no abstracts in English
Zn via thermodynamic measurementsKitazawa, Takafumi; Shimura, Yasuyuki*; Onimaru, Takahiro*; Haga, Yoshinori; Sakai, Hironori; Tokiwa, Yoshifumi; Kambe, Shinsaku; Yamamoto, Etsuji; Tokunaga, Yo
no journal, ,
no abstracts in English
Araki, Ryuhei; Hirose, Yusuke; Haga, Yoshinori; Kitazawa, Takafumi; Tokunaga, Yo; Onuki, Yoshichika*; Settai, Rikio*
no journal, ,
no abstracts in English
-UTeSakai, Hironori; Tabata, Chihiro; Kaneko, Koji; Tokiwa, Yoshifumi; Kitazawa, Takafumi; Kambe, Shinsaku; Tokunaga, Yo; Haga, Yoshinori
no journal, ,
We investigated single crystals of the van der Waals compound -UTe using microscopic techniques of nuclear magnetic resonance (NMR) and neutron diffraction. The conduction properties within the 
plane exhibit semiconductor-like behavior, while the magnetism displays easy-plane anisotropy. NMR measurements were performed to clarify the anisotropy of magnetic fluctuations in the paramagnetic state, revealing a significant enhancement of antiferromagnetic fluctuations with spins aligned along the 
axis. Furthermore, although an antiferromagnetic transition occurs at = 5K, the magnetic structure remained unclear. Neutron diffraction experiments were performed, yielding new insights into the magnetic structure. This presentation discusses the fundamental physical properties and magnetic characteristics of this compound.
