This article is cited in 4 papers

Ferroelectricity

Local structure of disordered PbSc$_{1/2}$Nb$_{1/2}$O$_3$ in the region of the diffuse tetragonal phase-rhombohedral phase transition

I. P. Alexandrova^a, A. A. Sukhovskii^a, Yu. N. Ivanov^a, I. P. Raevskii<sup>b

a</sup> L. V. Kirensky Institute of Physics, Siberian Branch of the Russian Academy of Sciences, Krasnoyarsk
^b Research Institute of Physics, Southern Federal University, Rostov-on-Don

Abstract: The local structure of the ferroelectric-relaxor PbSc$_{1/2}$Nb$_{1/2}$O$_3$ in the temperature range from 550 to 220 K has been investigated using $^{45}$Sc nuclear magnetic resonance. It has been found that, in the paraelectric phase at temperatures below 550 K, the crystal consists of regions of an ordered elpasolite structure and inclusions of the disordered tetragonal perovskite phase with displacements along directions of the [001] type. The relative weight of the tetragonal structure in the region of the paraelectric phase is approximately equal to 0.28. Below the temperature of the phase transition from the disordered modification to the polar phase, the relative weight of the tetragonal phase decreases with decreasing temperature. The tetragonal structure is replaced by the trigonal polar structure. In a wide temperature range ($\sim$50 K), there exists a heterophase structure that is characteristic of relaxors. Note that the correlation length of displacements in the tetragonal phase should be very small to explain the absence of indications of the existence of this phase in the diffraction data.

Received: 19.07.2011

 English version: Physics of the Solid State, 2012, 54:2, 316–323

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