Physico-Chemical nanomaterials science

Sources of occurrence and models of structural
ordering in PMN at low temperatures 
Lebedinskaya A.R.
Southern Federal University, Budennovskiy Av. 39 , Rostov-on-Don, 344090, Russia
E-mail: lebed1989@rambler.ru.

Ferroelectrics-relaxors, most of which are perovskite-like compounds with non-isovalent substitution by atoms of equivalent positions, were first synthesized more than 40 years ago and have since been actively studied in many laboratories of the world [1]. The study of ferroelectrics - relaxors is of interest from the point of view of searching for new highly efficient materials for ferroelectric memory devices, including optical recording of information.
PbMg1/3Nb2/3O3 (PMM) is a traditional model object for studying the physical properties of ferroelectrics-relaxors [2-3].
Numerous studies of the structural features of ferroelectrics-relaxors indicate the appearance of regions in the relaxors with sizes up to 100Å with a short-range composite order in the B sublattice without changing the cubic symmetry of the crystal. The electric field managed to induce a rhombohedral phase in these compounds. As a result of the investigations carried out, it was shown that the ferroelectric sublattice is the A sublattice, and not the B sublattice, in which the composite disorder is observed [4,5]. To date, a huge experimental material has been accumulated, many macroscopic properties of ferroelectrics-relaxors have been studied in detail, according to which the microscopic nature of the observed phenomena, in particular the nature of the low-temperature state, is still ambiguous.

1.	Smolensky G.A, Isupov V.A Ferroelectric properties of solid solutions of barium stannate in lead titanate. // ZhTF, 1954. – 24(8). - P. 1375 -1386.
2.	Vakhrushev S.B., Kiat J.-M. , Dkhil B. X-ray study of kinetics of field  induced transition from the glass-like to the ferroelectric phase in lead  magnoniobate.// Solid State Commun.- 1997. – 103 (8). – P. 477-482.
3.	Brown K.L., Stockdale C. P. J. , Luo H., Zhao X., Li J-F., Viehland D., Xu G.,  Gehring P.M., Ishida K., Hillier A.D.and Stock C. Depth dependant element analysis of PbMg1/3Nb2/3O3 using muonic X-rays // J. Phys.: Condens. Matter – 2018.-30, - P. 125703
4.	Lebedinskaya A.R., Kupriyanov M.F., Skulski R. Peculiarities of PMN structure below temperature of relaxor phase transition. // Materials Science and Engineering.-2001.-B83.-P.119-122.