Influence of Se, Pb and Mn impurities on the ferroelectric phase transition in gete studied by exafs

EXAFS was used to study the local environment of Se, Pb and Mn impurity atoms in germanium telluride. It is found that the three impurity atoms do not occupy fixed on-center positions in GeTe and that the origin and magnitude of the displacements are different. It is shown that the rate of decrease of Tc when doping GeTe with these impurities is determined primarily by the size of impurity atoms and the type of chemical bond between impurity and main atoms of the crystal.