Nuclear 111Cd probes detect hidden symmetry change at the gamma-alpha transition in cerium considered isostructural for 60 yearsстатья
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Дата последнего поиска статьи во внешних источниках: 20 сентября 2013 г.
Аннотация:We use the time differential perturbed angular correlation
technique to study nuclear electric quadupole hyperfine
interactions of probe $^{111}$Cd impurities in pristine cerium at
room temperature under pressures up to 8 GPa. We have found the
well known $\gamma-\alpha$ phase transition in Ce is not
isostructural. In $\alpha$-Ce the probe $^{111}$Cd atoms have
revealed a quadrupole electron charge density component which is
absent in $\gamma-$Ce. The hidden spacial structure of electronic
quadrupoles in $\alpha$-Ce is triple-$\vec{q}$
antiferroquadupolar, suggested by Nikolaev and Michel [Eur. Phys.
J. B {\bf 9}, 619 (1999)]. We relate our findings to the current
understanding of the $\gamma-\alpha$ phase transition and also
report on nuclear quadrupole interactions in other high pressure
phases of cerium: $\alpha''$ ($C2/m$ space symmetry) and $\alpha'$
($\alpha$-U structure)