119Sn solid state NMR and M\"ossbauer spectroscopic studies of the intermediate-valent stannide CeRuSn

TL;DR

This study uses 119Sn NMR and Mössbauer spectroscopy to investigate the local electronic and magnetic properties of the mixed-valent stannide CeRuSn, revealing temperature-dependent site distinctions and magnetic ordering.

Contribution

It provides the first detailed local-site analysis of CeRuSn using 119Sn NMR, confirming superstructure modulations and magnetic ordering at low temperatures.

Findings

Two distinct Sn sites at low temperatures with different shifts

Strong effects of crossover-like transitions between 100 and 280 K

Evidence of antiferromagnetic order at low temperatures

Abstract

The ternary stannide CeRuSn is a static mixed-valent cerium compound with an or-dering of trivalent and intermediate-valent cerium on two distinct crystallographic sites. 119Sn M\"ossbauer spectra showed two electronically almost identical tin atoms at 323 K, while at 298 K and below (77 and 4.2 K) two tin sites can clearly be distinguished. 119Sn solid state NMR experiments are performed to probe the local hyperfine fields at the two different Sn sites. 119Sn NMR powder spectra are nicely fitted with two Sn sites with nearly the same magnetic anisotropy, but with different absolute shift values. Both Sn sites are strongly affected by crossover-like transitions between 100 and 280 K. This local-site study confirms the superstructure modulations found in previous investiga-tions. Towards lower temperatures the powder spectra are broadened giving strong evidence for the antiferromagnetically ordered ground state.