PECULIARITIES OF PHASE TRANSITIONS IN PBFE_0.5NB_0.5O₃

Yu.Zakharov¹, L.Pustovaya¹, K.Abdulvakhidov¹, Yu.Kabirov¹, R.Kolesova¹, M.Kupriyanov¹, R.Skulski², Z.Surowiak².

¹Rostov University, 5 Zorge, Rostov-on-Don, 344090, Russia
²Silesian University, 2 Sniezna, Sosnowiec, 41-200 Poland

The peculiarities of the structure changes and the properties of lead ferroniobate (PFN) crystals and ceramics are investigated in the wide temperature and frequence ranges. The results of dielectric, pyroelectric studies in various temptratures are also presented. Structural measurments, as well as other physical measurments, shows

1. two phase transitions in about 354K and 388K;
2. in the paraelectric phase (at 433K) PFN crystal structure has small disordered shifts of the Pb atoms from their sites in the ideal perovskite structure.

This phenomena may be considered as an indication of the formation of metastable polarization regions in PFN crystals which are typical for ferroelectric relaxors.