Resonant inelastic X-ray scattering (RIXS) on magnetic EuCo$_2$P$_2$-based systems

The features of near-edge structure around the $L_3$–Eu absorption edge are investigated in EuCo$_2$P$_2$, Pr$_{1-x}$Eu$_x$Co$_2$P$_2$ ($x=0.2;0.4$), and Nd$_{0.6}$Eu$_{0.4}$Co$_2$P$_2$ by means of resonant inelastic X-ray scattering (RIXS). Europium is shown to be in the intermediate valence state in all compounds. A comparison is made of the values of europium intermediate valence obtained by different methods employing the synchrotron radiation. The correlation between europium valence and the observed changes of magnetic ordering in the systems under investigation is discussed.