Mössbauer Study of Properties and Phase Transitions of Ge_<i>x</i>Sn_1−<i>x</i>Te

Abstract

Abstract Results of a Mössbauer study of 119 Sn in Ge 0.1 Sn 0.9 Te and Ge 0.3 Sn 0.7 Te are reported and discussed. The effective Debye temperatures for recoilless absorption are about 160 and 180 °K, respectively. From the isomer shifts a percentage of covalent character in the bonding of at least 47 could be deduced. A marked decreasing of the recoilless fraction has been observed near the transition from the cubic to the rhombohedral structure: it has been explained theoretically on the assumption of a critical lowering in the phonon frequencies; a possible q and temperature dependence of the anomalous branch has been derived indirectly. Finally an increasing in the half‐width of the Mössbauer line has been observed on cooling in the rhombohedral phase and it was attributed to the appearance of a quadrupole interaction.