Metoki, Naoto; Aczel, A. A.*; Aoki, Dai*; Chi, S.*; Fernandez-Baca, J. A.*; Griveau, J.-C.*; Hagihala, Masato*; Hong, T.*; Haga, Yoshinori; Ikeuchi, Kazuhiko*; et al.
JPS Conference Proceedings (Internet), 30, p.011123_1 - 011123_6, 2020/03
Rare earths (4) and actinides (5) provide variety of interesting states realized with competing interactions between the increasing number of electrons. Since crystal field splitting of many-body electron system is smaller than the bandwidth, (1) high resolution experiments are needed, (2) essentially no clear spectrum with well defined peaks is expected in itinerant Ce and U compounds, and (3) Np and Pu is strictly regulated. Therefore, systematic research on magnetic excitations by neutron scattering experiments of localized compounds and rare earth iso-structural reference is useful. We describe the electron states of heavy electron compounds NpPdAl and actinide and rare earth based iso-structural family.
Metoki, Naoto; Yamauchi, Hiroki; Suzuki, Hiroyuki*; Kitazawa, Hideaki*; Hagihala, Masato*; Masuda, Takatsugu*; Aczel, A. A.*; Chi, S.*; Hong, T.*; Matsuda, Masaaki*; et al.
Journal of the Physical Society of Japan, 87(9), p.094704_1 - 094704_8, 2018/09
The -electron states of PrPdAl were revealed by neutron inelastic scattering. The flat -orbitals with large become stable under the two-dimensional CEF potential of unique crystal structure, which is the origin of the Ising anisotropy. A systematic understanding is possible in RPdAl based on this CEF potential. Especially the -type anisotropy in NpPdAl can be qualitatively understood with the positive Stevens factors. It mean that the local property is important for the physical properties of RPdAl including the heavy fermion superconductivity in NpPdAl.
Deng, Z.*; Jin, C. Q.*; Liu, Q. Q.*; Wang, X. C.*; Zhu, J. L.*; Feng, S. M.*; Chen, L. C.*; Yu, R. C.*; Arguello, C.*; Goko, Tatsuo*; et al.
Nature Communications (Internet), 2, p.1425_1 - 1425_5, 2011/08
In a prototypical ferromagnet (Ga,Mn)As based on a III-V semiconductor, substitution of divalent Mn atoms into trivalent Ga sites leads to severely limited chemical solubility and metastable specimens available only as thin films. The doping of hole carriers via (Ga,Mn) substitution also prohibits electron doping. To overcome these difficulties, Masek et al. theoretically proposed systems based on a I-II-V semiconductor LiZnAs, where isovalent (Zn,Mn) substitution is decoupled from carrier doping with excess/deficient Li concentrations. Here we show successful synthesis of Li(ZnMn)As in bulk materials. We reported that ferromagnetism with a critical temperature of up to 50 K is observed in nominally Li-excess compounds, which have p-type carriers.
MacDougall, G. J.*; Savici, A. T.*; Aczel, A. A.*; Birgeneau, R. J.*; Kim, H.*; Kim, S.-J.*; Ito, Toshimitsu*; Rodriguez, J. A.*; Russo, P. L.*; Uemura, Yasutomo*; et al.
Physical Review B, 81(1), p.014508_1 - 014508_7, 2010/01
MacDougall, G. J.*; Aczel, A. A.*; Carlo, J. P.*; Ito, Toshimitsu*; Rodriguez, J.*; Russo, P. L.*; Uemura, Yasutomo*; Wakimoto, Shuichi; Luke, G. M.*
Physical Review Letters, 101(1), p.017001_1 - 017001_4, 2008/07
We have performed zero-field muon spin rotation measurements on single crystals of LaSrCuO to search for spontaneous currents in the pseudo-gap state. By comparing measurements on materials across the phase diagram, we put strict upper limits on any possible time-reversal symmetry breaking fields that could be associated with the pseudo-gap. Comparison between experimental limits and proposed circulating current states effectively eliminates the possibility that such states exist in this family of materials.
Metoki, Naoto; Yamauchi, Hiroki; Kitazawa, Hideaki*; Suzuki, Hiroyuki*; Hagihara, Masato*; Masuda, Takatsugu*; Matsuda, Masaaki*; Aczel, A. A.*; Songxue, C.*; Hong, T.*; et al.
no journal, ,
In order to elucidate the 5-electron states in the heavy electron superconductor NpPdAl, neutron scattering experiments of the rare earth based iso-structural family have been carried out. The observed crystal field excitations of PrPdAl and NdPdAl were analyzed via the crystal field Hamiltonian with tetragonal symmetry, diagonalized analytically. The experimentally obtained crystal field parameters were very similar in CePdAl, PrPdAl, and NdPdAl, indicating a common effective charge potential in this series. We succeeded to clarify the 5 electron states of NpPdAl and UPdAl in comparison with these results.