In order to elucidate the nature of the exotic ordered phase of NpO 2 below T0 = 26 K, we have initiated the first 17O-NMR measurements on this system. From the 17O-NMR spectrum, the occurrence of two inequivalent oxygen sites has been confirmed below T0- It has also been shown that the characteristic features of the hyperfine interaction at the oxygen sites are well explained by invoking a hyperfine interaction with field-induced antiferromagnetic moments which appear as a result of the triple-q→ antiferroquadrupolar order. The NMR findings strongly support the occurrence of the longitudinal triple-q→ multipole structure in NpO2.
ASJC Scopus subject areas
- Physics and Astronomy(all)