Effect of a deviation from stoichiometry on the mössbauer parameters of Sn0.8Ge0.2Te during the phase transition

Abstract

The system of solid solutions (Sn0.8Ge0.2)1−yTey with the values of y = 0.499; 0.505; 0.510 is investigated by means of the Mössbauer effect on the 119Sn nucleus within the temperature range 160 to 300 K. The effective Debye temperature and mean‐square displacements of tin atoms from equilibrium are calculated. In the region of phase transition (about 200 K) fractures on the temperature dependencies of the isomer shift and Debye temperature are observed, while no anomalies of the Mössbauer effect probability are noticed. No quadrupole interaction is observed with the symmetry decrease in the lattice. A correlation between the isomer shift and interatomic distance is revealed. The ionicity of the chemical bond in the system SnxGe1−xTe is ≈︁ 54%, when x = 0.9, and about 40%, when x = 0.1.

Temperature investigations of the ferroelectric crystals and by means of Mössbauer spectroscopy

“…This means that the temperature changes in the line shift δ result only from δ SOD , and are not caused by changes in the electron density. The ionicity of the bond, estimated in the same way as in [22], makes up 0.7 for Sn 2 P 2 S 6 and 0.6 for Sn 2 P 2 Se 6 , and so is much higher than those observed for other chalcogenide compounds of tin. Moreover, in [7] the ionicity was found to increase to 0.93 and 0.92, respectively, when strontium and europium replaced tin atoms.…”

Mössbauer 119Sn and XPS spectroscopy of Sn2P2S6 and SnP2S6 crystals

“…The accelerating voltage of 1 kV and the beam current of 20 μA cm -2 were used (etching rate ∼4 nm min -1 ). Sn 2 P 2 S 6 and SnP 2 S 6 samples were prepared and investigated by means of Mössbauer spectroscopy as described earlier [13,17]. The Mössbauer spectrometer equipped with the Mössbauer furnace (Wissenschaftliche Electronik GMBH) was applied for measurements at temperatures up to 450 K. For the measurements within the 6-300 K temperature range a closed cycle cryostat (Advanced Research Systems, Inc.) suitable for Mössbauer spectroscopy was used.…”