NMR study on AmO2: Comparison with UO2 and NpO2

作者：Tokunaga Yo^*; Nishi Tsuyoshi; Kambe Shinsaku; Nakada Masami; Homma Yoshiya; Sakai Hironori; Chudo Hiroyuki

来源：Journal of the Physical Society of Japan, 2011, 80: SA110.

• actinide dioxide
• NMR
• phase transition
• self-radiation effect

Recently, O-17 NMR has been performed for the first time on AmO2. We have observed a drastic broadening of the NMR spectrum, along with a sudden drop of NMR signal intensity, below T-0 = 8.5 K. These data provide the first microscopic evidence for a phase transition at this temperature as a bulk property of this system. In this paper, we compare NMR results for AmO2 with those from UO2 and NpO2. In the ordered state we have recorded an O-17 NMR spectrum with a triangular line shape, which resembles neither that of UO2 nor NpO2. This spectrum indicates that the internal local field H-int is distributed very nearly randomly from zero to a maximum value, that is, H-int(max) similar to 7kOe. The temperature dependences of the Knight shift and the nuclear relaxation rate are also compared.

• 出版日期2011-7