X-ray-absorption spectroscopy investigation of the martensitic structural transformation in theRCu (R=rare earth) series

Abstract

We present an x-ray-absorption spectroscopy (XAS) investigation performed at the ${\mathit{L}}_{1,3}$ edges of the rare earth Y K edge and K and ${\mathit{L}}_{2,3}$ edges of copper in several R-Cu intermetallic compounds: RCu (R=Y,Gd,Tb), ${\mathrm{Y}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Tb}}_{\mathit{x}}$Cu, and ${\mathrm{Y}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Tb}}_{\mathit{x}}$ ${\mathrm{Cu}}_{\mathit{y}}$ ${\mathrm{Ag}}_{1\mathrm{-}\mathit{y}}$. XAS spectra at the different absorption edges evidence the apparition of a strong electronic perturbation in the systems after the martensitic transformation. The dynamics of the structural transformation is discussed in terms of the interplay between the modification of both d-band widening and s-d transfer pressure.