4f-local magnetic moments in the metals and alloys with SDW-instability

Distinct itinerant spin-density waves and local-moment antiferromagnetism in an intermetallic ErPd2Si2 single crystal

“…We also build a detailed knowledge of the virtual coupling between both states, which is actually intractable in 3 d -metallic systems. Our findings correspond to theoretical predictions 49 and thus establish a new model material.…”

“…Figures 3 and 4 show clearly the coexistence and competition between the two modulated orders, which can be explained through a mechanism where conduction electrons contribute to both a SDW state, through Fermi surface nestings and s-f couplings 49 , and to mediating the dominant RKKY interactions between localized 4 f moments 40 . These two functions are in general competitive, leading to a breakdown of the SDW state as the local-moment magnetism starts to fully develop below ~2.9 K. A similar breakdown also occurs in the field dependence, where the fragile SDW state is suppressed above ~0.17 T. Once above the field threshold, those conduction electrons that contribute to the SDW state then decouple and participate in the RKKY exchanges.…”

“…This clearly indicates that I ± and I C have different electron origins. Combining these five points leads us to propose that the I C peaks are due to a SDW state, which is a consequence of the weak (in view of the small threshold field) electron-electron interactions [25] mediated by the 4f moments [49], plausibly associated with the itinerant conduction electrons near the Fermi level.…”

“…1) tetragonal I4/mmm structure (a = b = 4.0987(1) Å, and c = 9.8762(1) Å at ambient conditions, as listed in Table 1) as that of the family of 122-iron-pnictides [45][46][47] and exhibit a wide range of interesting physical properties, e.g., pressure-induced superconductivity in CePd 2 Si 2 and anomalous valence fluctuations in EuPd 2 Si 2 [48]. Early theoretical proposals [49] for the 4f conductors with extended RKKY-interactions predicted that localized 4f moments can promote a SDW state in the itinerant conduction electrons. So far, to our knowledge, no clear example of such a material with distinguishable propagation vectors has been identified.…”