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Toyama, Takeshi*; Suzudo, Tomoaki; Nagai, Yasuyoshi*; 9 of others*
Journal of Nuclear Materials, 556, p.153176_1 - 153176_7, 2021/12
Times Cited Count：2 Percentile：30.55(Materials Science, Multidisciplinary)We performed a high-precision investigation of radiation-enhanced diffusion (RED) using electron irradiation and three-dimensional atom probe (3D-AP). Cu-Fe diffusion pairs were created using high-purity Fe and Cu as base materials, and irradiated by 2 MeV electron. Cu diffusion into the Fe matrix was observed at the atomic level using 3D-AP, and the diffusion coefficient was obtained directly using Fick's law. RED was clearly observed, and the ratio of diffusion under irradiation to thermal diffusion was enhanced at low temperature. RED was quantitatively evaluated using the reaction kinetics model, and the model which consider only vacancies gave a good agreement. This gave experimental clarification that RED was dominated by irradiation-induced vacancies. In addition, the direct experimental results on the effect of irradiation on the solubility limits of Cu in Fe was obtained; solubility limits under irradiation were found to be lower than those under thermal aging.
Sc
)
O
single crystalsUtsumi, Shigenori*; Tanaka, Seiya*; Maruyama, Kenichi*; Amako, Yasushi*; Kiyanagi, Ryoji; Nakao, Akiko*; Moriyama, Kentaro*; Ishikawa, Yoshihisa*; 9 of others*
ACS Omega (Internet), 5(38), p.24890 - 24897, 2020/09
Times Cited Count：4 Percentile：20.61(Chemistry, Multidisciplinary)Fabricating large, high-crystalline-quality single-crystal samples of hexagonal ferrite Ba(FeSc)O is the first important step to elucidating its helimagnetic structure and developing it for further applications. In this study, single crystals of Ba(FeSc)O of various Sc concentrations 
were successfully grown by the spontaneous crystallization method using Na
O-FeO
flux. X-ray diffraction and elemental analysis revealed that the obtained crystals were composed of single-phase Ba(FeSc)O of high crystalline quality. The temperature dependence of magnetization and the magnetization curves at 77 K of the = 0.128 crystal exhibited behavior characteristics of helimagnetism. Neutron diffraction measurements of the = 0.128 crystal exhibited magnetic satellite reflection peaks below 211K, proving evidence that Ba(FeSc)O behaves as a helimagnetic material.
