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revealed by 
O-NMRTokunaga, Yo; Nishi, Tsuyoshi; Nakada, Masami; Ito, Akinori*; Sakai, Hironori; Kambe, Shinsaku; Homma, Yoshiya*; Honda, Fuminori*; Aoki, Dai*; Walstedt, R. E.*
Physical Review B, 89(21), p.214416_1 - 214416_8, 2014/06
Times Cited Count：7 Percentile：31.81(Materials Science, Multidisciplinary)The magnetic phase transition near 
K in AmO has been investigated microscopically by means of O NMR. To avoid complexities arising from sample aging associated with the alpha decay of 
Am, all measurements have been performed within 40 days after sample synthesis. Even during such a short period, however, a rapid change of NMR line shape has been observed at 1.5 K, suggesting that the ground state of AmO is very sensitive to disorder. We have also confirmed the loss of O NMR signal intensity over a wide temperature range below 
, and more than half of oxygen nuclei are undetectable at 1.5 K. This behavior reveals the persistence of slow and distributed spin fluctuations down to temperatures well below . In the paramagnetic state, strong NMR line broadening and spatially inhomogeneous spin fluctuations have been observed. The results are all indicative of short-range, spin-glass-like character for the magnetic transition in this system.
Hakushi Gakui Rombun, 00(00), p.1 - 265, 1997/00
no abstracts in English
studied by O-NMRTokunaga, Yo; Nishi, Tsuyoshi; Nakada, Masami; Ito, Akinori*; Sakai, Hironori; Kambe, Shinsaku; Homma, Yoshiya*; Honda, Fuminori*; Aoki, Dai*; Walstedt, R. E.*
no journal, ,
We will present the result of our recent NMR study performed to elucidate the origin of magnetic phase transition near K in AmO. To avoid complexities arising from sample aging associated with the alpha decay of Am, all measurements have been performed within 40 days after sample synthesis. Even during such a short period, however, a rapid change of NMR line shape has been observed at 1.5 K, suggesting that the ground state of AmO is very sensitive to disorder. We have also confirmed the loss of O NMR signal intensity over a wide temperature range below , and more than half of oxygen nuclei are undetectable at 1.5 K. This behavior reveals the persistence of slow and distributed spin fluctuations down to temperatures well below . The results are all indicative of short-range, spin-glass-like character for the magnetic transition in this system.
Pu
Cm
NNishi, Tsuyoshi; Hayashi, Hirokazu; Hatakeyama, Yuichi; Kurata, Masaki
no journal, ,
no abstracts in English
Takano, Masahide; Takaki, Seiya
no journal, ,
In the fuel containing minor actinides with high concentrations, lattice defects and He atoms accumulates quickly due to the self-irradiation damage of alpha-decay. The lattice expansion arising from the defects accumulation is well-known phenomenon, however, the knowledge relating to the bulk expansion have not been obtained yet. In this work we prepared a nitride fuel pellet containing 
Cm as a main alpha-emitter, and obtained data on the relationship between lattice and bulk expansion as a function of storage duration at room temperature.
Takano, Masahide; Takaki, Seiya
no journal, ,
To clarify the influence of high temperature He gas release on the MA transmutation fuel behavior, annealing experiments on a Cm-bearing nitride pellet were carried out after two years of storage at room temperature, and the results were compared with those on the Cm-bearing dioxide. Just before the annealing, the nitride pellet showed the large expansion value of 1.1%, which suggests that vacancies in grains formed voids at room temperature. During the annealing experiments, the gas swelling of the nitride pellet due to He release above 800
C was relatively slight. From the microstructure images, smaller grains and higher open-porosity of the nitride pellet resulted in the slight gas swelling. After the annealing at 1300C, the nitride pellet still had expansion value of 0.6%, that should be taken into account when designing the pellet-cladding gap.
