XPS Investigation of $Y_{1-x}Dy_xNi_2B_2C$ Superconductors

The analysis of the valence band photoemission spectra of $Y_{1-x}Dy_xNi_2B_2C$ (0≤x≤1) is presented. The valence bands are mainly plotted for Ni 3d, Y 4d and Dy 4f contributions, according to theoretical predictions. The valence bands of $Y_{1-x}Dy_xNi_2B_2C$ compounds markedly change shape with the x parameter, especially in the binding energy region from 3 eV to 14 eV. For large content of Dy (above 55%) the valence band is predominant by Dy 4f states whereas Ni 3d states govern the valence band of yttrium rich compounds. Changing in domination of valence sub-band correlates with plot of superconducting transition temperature $T_c$ with Dy concentration.