Identification of Quadrupolar Excitation Channels at theL3Edge of Rare-Earth Compounds

Resonant inelastic x-ray scattering spectra are recorded at the $L_3$ absorption edge of rare-earth ions in $R_2{\mathrm{Fe}}_{14}\mathrm{B}$. In all cases, weak resonances are observed at energies below the dipolar white line resonance, originating from $2p\to 4f$ quadrupolar excitations. Their energy position is in excellent agreement with that of preedge features in the x-ray magnetic circular dichroism (XMCD) spectra of the same samples. Our results therefore evidence the systematic appearance of quadrupolar excitation channels and the importance of their inclusion in the correct interpretation of the XMCD at the $L_3$ edges of rare-earth systems.