NMR INVESTIGATION OF MIXED RELAXORS XPMN-(1-X)PSN

Measurement of Nb-93, Sc-45, Pb-207 NMR Spectra are performed for the first time in the solid solution of the ferroelectric relaxors xPMN-(1 -x)PSN (0 less than or equal to x less than or equal to 1). The peculi ar behavior of the observed quantities and parameters, e.g. disappeara nce of dielectric dispersion for x approximate to 0.5, was explained b y NMR measurements for the first time. The analysis of Sc-45 NMR spect ra dependence on x has shown that for x greater than or equal to 0.5 t he ordering of the regions containing Sc ions takes place. The depende nce of the level of structural order on solid solution composition is obtained. The investigation and analysis of temperature dependence of Nb-93 and Sc-45 NMR line width of the end member of the considered sol id solution PSN made it possible to obtain new information about ions shifts and dynamics. It was shown that at T < T-max Nb and Sc ions are shifted from their equilibrium lattice site (T-max is dielectric perm ittivity epsilon' maximum position). These ions shifts contribute to t he temperature dependence of lattice polarization P, meanwhile jump of P at T = T-max is determined by Pb ions shifts. The Nb ions electric diploes were shown to be static in PSN in NMR measurements scale (10(- 7) s) contrary to essential Nb dipoles reorientation dynamic behavior in PMN. The peculiarities of NMR line form in the investigated materia ls gave evidence about distribution of Nb, Sc, Pb dipole moments direc tions as well as values at any constant temperature.