Invariant Form of Hyperfine Interaction with Multipolar Moments – Observation of Octupolar Moments in NpO2 and Ce1-xLaxB6 by NMR –

摘要: The invariant form of the hyperfine interaction between multipolar moments and nuclear spin is derived, applied to discuss possibilities identify antiferro-octupolar (AFO) by NMR experiments. ordered phase NpO$_{2}$ IV Ce$_{1-x}$La$_{x}$B$_{6}$ are studied in detail. Recent $^{17}$O for polycrystalline samples discussed theoretically from our formulation. observed feature splitting spectrum into a sharp line broad line, their intensity ratio, magnetic field dependence shift width can be consistently explained on basis triple $\bq$ AFO ordering model proposed Paix\~{a}o {\it et. al.} Thus, present theory shows that gives strong support model. 4 O sites fcc NpO$_2$ become inequivalent due secondary AF-quadrupoles: one cubic three non-cubic sites. It turns out antiferro-dipole induced field, quadrupolar at key ingredients understand spectrum. controversial problem nature also studied. pointed there unique spectra, if $\Gamma_{5}$($T^{\beta}_{x}=T^{\beta}_{y}=T^{\beta}_{z}$) realized Ce$_{1-x}$La$_{x}$B$_{6}$. Namely, B atom pair $({1/2},{1/2},\pm u)$ crosses zero $(1\bar{1}0)$ plane when rotated around $[001]$ axis.