Tuning the Eu valence in EuPd_3B_x: pressure versus valence electron   count - a combined computational and experimental study
  In a joint theoretical and experimental study we investigate the pressure dependence of the Eu valence in EuPd_3B_x (0 <= x <= 1). Density functional band structure calculations are combined with x-ray absorption and x-ray diffraction measurements under hydrostatic pressures up to 30 GPa. It is observed that the heterogenous mixed-valence state of Eu in EuPd_3B_x (x >= 0.2) can be suppressed partially in this pressure range. From the complementary measurements we conclude that the valence change in EuPd_3B_x is mainly driven by the number of additional valence electrons due to the insertion of boron, whereas the volume change is a secondary effect. A similar valence change of Eu in Eu_{1-x}La_xPd_3 is predicted for x >= 0.4, in line with the suggested electron count scenario. 
M. Schmitt, R. Gumeniuk, A. Trapananti, G. Aquilanti, C. Strohm, K.   Meier, U. Schwarz, M. Hanfland, W. Schnelle, A. Leithe...
cond-mat.str-el