J. Phys. Soc. Jpn. 75S (2006) pp. 33-35  |Previous Article| |Next Article|  |Table of Contents|
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Proc. of 5th Int. Symposium on ASR-WYP-2005 – Advances in the Physics and Chemistry of Actinide Compounds –

Multipolar Phase Transition in NpO₂: Comparison with UO₂ from ¹⁷O-NMR

Yo Tokunaga¹, Yoshiya Homma², Shinsaku Kambe¹, Dai Aoki², Kenji Ikushima¹, Hironori Sakai¹, Shyugo Ikeda¹, Etsuji Yamamoto¹, Akio Nakamura¹, Yoshinobu Shiokawa^1,2, Tatsuya Fujimoto¹, Russell E. Walstedt¹ and Hiroshi Yasuoka¹

We review our recent ¹⁷O-NMR results on NpO₂. The compound is suggested to exhibit a magnetic octupolar phase transition at T₀=26 K. From the temperature dependence of ¹⁷O-NMR spectrum, the occurrence of two inequivalent oxygen sites has been confirmed below T₀. Furthermore, a dramatic dependence of nuclear spin-lattice relaxation rates on applied field has been observed above and below T₀. These NMR results contrast sharply with those for the antiferromagnet UO₂ and thus highlight the exotic nature of the phase transition in NpO₂.

URL: http://jpsj.ipap.jp/link?JPSJS/75S/33/
DOI: 10.1143/JPSJS.75S.33

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