We have initiated the first 17O-NMR measurements in the ordered state of NpO 2. From the 17O-NMR spectrum, we have confirmed the occurrence of two inequivalent oxygen sites below T0 = 26 K. It has also been shown that the 17O-NMR spectrum in the ordered state can be understood by considering an unconventional hyperfine interaction between the 17O nuclear spins and field-induced antiferromagnetic moments arising from the longitudinal triple- q antiferro-quadrupolar order. These NMR results give strong evidence for the occurrence of the longitudinal triple- q multipole structure in NpO 2.
- Quadrupolar/octupolar ordering
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering