Solid-state ¹¹⁹Sn NMR and M¨ossbauer Spectroscopic Studies of the Intermediate-valent Stannide CeRuSn

Abstract

The ternary stannide CeRuSn is a static mixed-valent cerium compound with an ordering of trivalent and intermediate-valent cerium on two distinct crystallographic sites. 119 Sn Mössbauer 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. Solid-state 119 Sn NMR experiments were performed to probe the local hyperfine fields at the two different Sn sites. Powder 119 Sn NMR 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 investigations. Towards lower temperatures the powder NMR spectra are broadened giving strong precursor evidence for the antiferromagnetically ordered ground state.

Nature of the magnetic ground state in the mixed valence compound CeRuSn: a single-crystal study

“…The formation of new superstructures and coexistence of two or more Ce sites with different valence states in CeRuSn was predicted by ab initio band structure calculations performed for CeRuSn by Matar et al [11] and was corroborated also by results of 119 Sn NMR and Mössbauer spectroscopy measurements [15].…”

The Solid Solutions (Ce1-xLax)RuSn

“…Thus, also the 119 Sn spectra point to the subcell structure. In contrast, the spectra of pure CeRuSn [11] show a superposition of two sub-spectra of the two crystallographically independent tin sites. The experimental line widths of the x = 0.2 and 0.5 samples are only slightly enhanced.…”

Intermediate-valent CeCoAl – a commensurate modulated structure with short Ce–Co distances

“…Future studies will focus on the synthesis of larger quantities of phase-pure CeCoAl for detailed physical property studies for comparison with the CeRuSn [18][19][20][21][22][23][24][25][26][27][28][29] data. Tab.…”

“…Among the large number of equiatomic CeTX intermetalllics (T = electron-rich transition metal; X = element of the 3rd, 4th or 5th main group) [1][2][3][4][5], CeCoAl [6][7][8][9][10][11][12][13][14], CeCoGa [6,[15][16][17], and CeRuSn [18][19][20][21][22][23][24][25][26][27][28][29] exhibit unusual crystal chemistry. These three intermetallics have the same valence electron count and the same subcell structure which derives from the Bi 2 Pd type [30][31][32], space group C2/m, through an ordering of the cerium and aluminum (gallium, tin) atoms on the bismuth sites.…”