EXAFS study of the influence of impurities on the phase transition in GeTe

EXAFS technique was used to study the local environment of Se, Pb, Sn, Mn and In impurity atoms in germanium telluride. These data were used to clarify the mechanisms by which the impurity influence the phase transition temperature T_c. It was shown that the rate of decrease of T_c in doped GeTe is determined primarily by the charge state of impurity, the type of the chemical bond between impurity and main atoms of the crystal and by the size of impurity atoms.

Keywords: ferroelectric phase transition, impurity effects, Curie temperature, off-center atoms, local structure, EXAFS spectroscopy, selenium, lead, tin, manganese, indium

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