Electronic structure of(Ce1−xNdx)3Alprobed by resonant x-ray emission spectroscopy

Abstract

Bulk-sensitive measurements of the electronic structure of Ce in the ${({\text{Ce}}_{1\ensuremath{-}x}{\text{Nd}}_{x})}_{3}\text{Al}$ system have been performed as a function of temperature and $x$ using x-ray absorption spectroscopy in the partial fluorescence yield mode and resonant x-ray emission spectroscopy (RXES) at the $\text{Ce}\text{ }{L}_{3}$ edge. In the Ce-rich samples, the RXES spectra indicate a mixed-valence state consisting mainly of ${f}^{1}$ with a small fraction of ${f}^{0}$ and ${f}^{2}$. The ${f}^{1}/{f}^{2}$ intensity ratio is found to undergo a first-order transition at low temperature, coinciding with the $\ensuremath{\alpha}\ensuremath{\rightarrow}\ensuremath{\gamma}$ structural transition. Following the disappearance of the Kondo effect at $x>0.2$, the ${f}^{1}/{f}^{2}$ intensity ratio is found to significantly increase with $x$, signifying a weakening of the mixed-valence character. The fact that the volume remains nearly constant upon Nd doping points to an electronic origin of the $x$ dependence of the $\text{Ce}\text{ }{f}^{1}/{f}^{2}$ intensity ratio.