Pseudo-triplet 5 electron state in the heavy fermion superconductor NpPdAl

Metoki, Naoto; Aoki, Dai*; Griveau, J.-C.*; Otsuki, Junya*

Journal of the Physical Society of Japan, 89(2), p.024707_1 - 024707_6, 2020/02

https://doi.org/10.7566/JPSJ.89.024707

The pseudo triplet ground state in the heavy-fermion superconductor NpPdAl was concluded. The magnetic susceptibility can be reproduced by the singlet ground state with the main component of and the first excited doublet dominated by at ,K. The magnetization curve can be explained from the effective local hamiltonian for pseudo spin =1 with () equivalent to the quadrupole operator . The specific heat can be described with the Kondo model normalized to give the entropy R, corresponding to the pseudo triplet state. The derived Kondo temperature ,K comparable to the level splitting ,K indicates the contribution of the excited doublet to the possible multi-channel Kondo effect.

Incommensurate longitudinal SDW state with a long periodicity in UCuSi

Honda, Fuminori; Metoki, Naoto; Matsuda, Tatsuma; Haga, Yoshinori; Onuki, Yoshichika

Journal of the Physical Society of Japan, 75(Suppl.), p.121 - 123, 2006/08

no abstracts in English

Itinerant 5 electrons and the Fermi surface properties in an enhanced Pauli paramagnet NpGe

Aoki, Dai*; Yamagami, Hiroshi*; Homma, Yoshiya*; Shiokawa, Yoshinobu; Yamamoto, Etsuji; Nakamura, Akio; Haga, Yoshinori; Settai, Rikio*; Onuki, Yoshichika

Journal of the Physical Society of Japan, 74(8), p.2149 - 2152, 2005/08

https://doi.org/10.1143/JPSJ.74.2149

no abstracts in English

Theoretical analysis of electronic structure for the chemical bonding of Pu and Am in MgO

Tanaka, Kumiko; Hirata, Masaru; Sekine, Rika*

Journal of Nuclear and Radiochemical Sciences, 5(2), p.27 - 31, 2004/12

https://doi.org/10.14494/jnrs2000.5.27

The relativistic discrete-variational Dirac-Fock-Slater (DV-DFS) method was performed to investigate the electronic structure of MgO doped with Pu or Am atoms. The differences between these systems, in particular, the participation of d-electrons and f-electrons in chemical bonding, were clarified by calculating their electronic structures. Substitution of actinide atoms was found to result in the effective charges of MgO becoming smaller, with a large charge transfer occurring as far as the second layer. It was also found that the bonding feature between the center atom and the surrounding oxygen atoms was extended to lower energy in the case of actinide (An) substituted systems. Moreover, the bonding characteristics were assigned; a bonding interaction for An6d-O2p and an anti-bonding for An5f-O2p near the HOMO level. These complex effects were found to dominate the strength of the covalent bonding between MgO and actinide atoms.

Empirical evaluation of the thermodynamic and magnetic properties from the atomic distances of NaCl-type actinide compounds

Omichi, Toshihiko*; Arai, Yasuo

Journal of Nuclear Science and Technology, 39(Suppl.3), p.156 - 159, 2002/11

http://www.tandfonline.com/doi/abs/10.1080/00223131.2002.10875432

no abstracts in English

Neutron scattering study of the crystal and magnetic structures in itinerant-5f antiferromagnets UNiGa and UPtGa

Tokiwa, Yoshifumi; Haga, Yoshinori; Metoki, Naoto; Ishii, Yoshinobu; Onuki, Yoshichika

Journal of the Physical Society of Japan, 71(3), p.725 - 728, 2002/03

https://doi.org/10.1143/JPSJ.71.725

no abstracts in English

A study on properties of uranium oxide using band theory

Tejima, Shogo

JNC TN8400 2000-029, 54 Pages, 2000/10

JNC-TN8400-2000-029.pdf:1.32MB

This report describes the study done by the author as a postdoctoral research associate at Japan Nuclear Cycle Development Institute. This report is divided into three parts: construction of a relativistic band calculation formalism based on the density functional theory, using this method, investigation of the electrical properties for ferromagnetic UGe and antiferromagnetic UO. (1)A relativistic band calculation (RBC) method. Band calculations for the s, p, and d electric structure have been developed well in the practical application and theoretical study. But band calculation method treating magnetic 5f electrons as actinide compounds are complicated and needed relativistic approach, so it is behind with the study of the 5f system. In this study we construct the relativistic band calculationformalism valid for magnetic 5f electrons. (2)Electric properties of UGe. The actinide compounds UGe is ferromagnetic, so the theoretical analysis is not well yet. The electric structure and fermi surface of UGe are analyzed using the RBC. The theoretical results show that UGe is heavy electron with the 5f character and are agreement with experimental one. (3)Electric structure of nuclear fuel UO. It is important to understand the mechanism of the thermal conductivity of nuclear fuel as antiferromagnetic UO. The UO band calculation reflecting the thermal properties, into account of relativistic effect, have not done yes. So using the RBC the detailed electric structure of UO are obtained.

Electronic structure and geometry optimization of hexavatent plutonyl nitrate by the relativistic density functional calculation

Hirata, Masaru; Bastug, T.; Tachimori, Shoichi

Nihon Genshiryoku Gakkai-Shi, 42(10), p.1104 - 1108, 2000/10

https://doi.org/10.3327/jaesj.42.1104

no abstracts in English

Observation of U NMR in the Antiferromagnetic state of UO

*; *; Tsutsui, Satoshi*; Saeki, Masakatsu; Nasu, Saburo*; *

Journal of the Physical Society of Japan, 67(1), p.65 - 66, 1998/01

https://doi.org/10.1143/JPSJ.67.65

no abstracts in English

Moessbauer study of uranium compounds

Tsutsui, Satoshi*; Nakada, Masami; Kobayashi, Yasuhiro*; ; Saeki, Masakatsu; Nasu, Saburo*; Nakamura, Akio; Haga, Yoshinori; Homma, Tetsuo*; Yamamoto, Etsuji; et al.

Physics of Strongly Correlated Electron Systems (JJAP Series 11), p.266 - 268, 1998/00

no abstracts in English