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

High magnetic field specific heat of a quasi-degenerate Kondo alloy (Lu, Yb)RhZn

Kitazawa, Takafumi; Ikeda, Yoichi*; Imajo, Shusaku*; Haga, Yoshinori; Kohama, Yoshimitsu*; Tokunaga, Yo; Fujita, Masaki*

no journal, , 

no abstracts in English

Pulsed high field measurements in quasi-degenerate diluted Yb systems (Lu,Yb)RhZn

Kitazawa, Takafumi; Haga, Yoshinori

no journal, , 

no abstracts in English

Pulsed high magnetic field measurements in a quasi-degenerate diluted Yb system (Lu,Yb)RhZn

Kitazawa, 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.

Crystal structure and low-temperature properties of uranium-containing Tsai-type approximant Al-Au-U

Haga, Yoshinori; Tokiwa, Yoshifumi; Sakai, Hironori; Kitazawa, Takafumi; Yamamoto, Etsuji; Kambe, Shinsaku; Tokunaga, Yo; Ikarugi, Riko; Muro, Yuji*

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, , 

Single crystals of the uranium-based van der Waals compound UTe were grown. Neutron diffraction experiments were carried out to determine its magnetic structure. This compound's physical and magnetic properties will be reported.