Multiorbital Kondo effect in a diluted-Yb system (Lu,Yb)RhZn

Kitazawa, Takafumi

Hamon, 35(3), p.119 - 122, 2025/08

Observation of field-induced single-ion magnetic anisotropy in a multiorbital Kondo alloy (Lu,Yb)RhZn

Kitazawa, 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

https://doi.org/10.1103/PhysRevB.108.085105

Magnetic property of neptunyl (+2) complex NpO(CHO)(CHN)

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.

Molecular magnetism of neptunyl (+2) complex NpO(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

A New type of neptunyl(VI) hydroxide which is topologically similar to -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

https://doi.org/10.1246/bcsj.76.1375

no abstracts in English

Basic physical properties of single crystalline HoCoZn

Kitazawa, Takafumi; Shimura, Yasuyuki*; Onimaru, Takahiro*; Haga, Yoshinori; Sakai, Hironori; Tokiwa, Yoshifumi; Kambe, Shinsaku; Yamamoto, Etsuji; Tokunaga, Yo

no journal, , 

no abstracts in English

Incommensurate antiferromagnetic order of the Ising moment in -UTe

Sakai, 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.

Pulsed high field magnetization measurements in single crystals of the diluted Yb system (Lu, Yb)RhZn

Kitazawa, Takafumi; Tokunaga, Yo; Haga, Yoshinori; Opletal, P.; Sakai, Hironori; Tokiwa, Yoshifumi; Yamamoto, Etsuji; Kambe, Shinsaku

no journal, , 

no abstracts in English

Magnetism in uranium-based van der Waals compound -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.

Basic physical properties and precise ground state of HoCoZn

Kitazawa, Takafumi; Shimura, Yasuyuki*; Onimaru, Takahiro*; Haga, Yoshinori; Sakai, Hironori; Tokiwa, Yoshifumi; Kambe, Shinsaku; Yamamoto, Etsuji; Tokunaga, Yo

no journal, , 

We investigated the magnetic properties of HoCoZn, a cubic compound that is a candidate material for realizing the three-channel Kondo effect (3CK). Macroscopic physical measurements revealed antiferromagnetic ordering below 0.6 K. Analysis of magnetization data above 2 K suggests a crystalline-electric field (CEF) ground state, in which 3CK is theoretically expected to occur. However, discrepancies between the experimental and calculated specific heat at very low temperatures were observed due to nuclear specific heat at Ho sites. By incorporating hyperfine coupling into the model, we successfully reproduced the experimental data and demonstrated that the CEF ground state is split by hyperfine interactions on the order of 1 K. In this talk, we will present details of the 4-electron ground state and discuss the possible emergence of 3CK in cubic Ho-based compounds.