Cluster spin-glass-like behavior in heavy-fermion-filled cage Ce3Co4Sn13 doped with Fe: Magnetic and Mössbauer effect studies

We have measured the electric transport, magnetic properties, electronic structure, and $^{119}\text{Sn}$ M\"ossbauer spectra of a series of skutterudite-related ${\mathrm{Ce}}_{3}{\mathrm{Co}}_{4\ensuremath{-}x}{\mathrm{Fe}}_{x}{\mathrm{Sn}}_{13}$ compounds, where $x$ varies from 0 to 0.5. On the basis of these comprehensive studies, we report an observation of the spin-glass phase for samples with $xg0.1$ Fe doping. The effect is, however, not observed for Ni dopants. The critical concentration close to $x=0.1$ separates the magnetically ordered phase with $xg0.1$ from the dense Kondo lattice phase ($x\ensuremath{\le}0.1$) with weak magnetic correlations. The M\"ossbauer spectra consist of three quadrupole doublets, related to covalent bonding among Sn2 and Ce as well as between Sn2 and Co/Fe atoms, which could be a reason for the structural deformation of the cages. These results confirm earlier structural investigations and are in agreement with the band-structure calculations, both of which indicated strong covalent bonding between the atoms $M$, Sn1, or Ce in the center of the cages and the Sn2 atoms forming the respective cages.