Peculiarities of PMN structure below temperature of relaxor phase transition

The results of investigations of PMN single crystal atomic structure at tem peratures 103, 183 and 203 K (i.e. below the temperature of dielectric perm ittivity maximum - T-m) shown that elementary cell parameters change non-mo notonically at temperatures lower then T-m (T-m approximate to 240 K). By t hat Debay-Waller factors (DWF's) of Pb atoms are considerably greater than DWF's of another atoms in PMN, also it has been stated that disordered shif ts of Pb atoms in x- and y-directions increase with decreasing temperature (for T < T-m). (C) 2001 Elsevier Science B.V. All rights reserved.