Title: Ferroelectric and dielectric characterization studies on relaxor- and ferroelectric-like strontium-barium niobates
Author(s):

	K. Matyjasek (Institute of Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology, Al. Piastow 48, 70-310 Szczecin, Poland) ,
	J. Dec (Institute of Materials Science, University of Silesia, 12 Bankowa St., 40-007 Katowice, Poland) ,
	S. Miga (Institute of Materials Science, University of Silesia, 12 Bankowa St., 40-007 Katowice, Poland) ,
	T. Łukasiewicz (Institute of Electronic Materials Technology, 133 Wólczyńska Str. 01-919 Warsaw, Poland)

Ferroelectric domain structure evolution induced by an external electric field was investigated by means of nematic liquid crystal (NLC) method in two strontium-barium niobate single crystals of nominal composition: Sr_0.70Ba_0.30Nb₂O₆ (SBN:70 - relaxor) and Sr_0.26Ba_0.74Nb₂O₆ (SBN:26 - ferroelectric). Our results provide evidence that the broad phase transition and frequency dispersion that are exhibited in SBN:70 crystal have a strong link to the configuration of ferroelectric microdomains. The large leakage current revealed in SBN:26 may compensate internal charges acting as pinning centers for domain walls, which gives rise to a less restricted domain growth similar to that observed in classical ferroelectrics. Microscale studies of a switching process in conjunction with electrical measurements allowed us to establish a relationship between local properties of the domain dynamics and macroscopic response i.e., polarization hysteresis loop and dielectric properties.

Key words: relaxor ferroelectrics, niobates, domain walls, switching process, SBN
PACS: 77.80.Dj, 77.80.Fm, 77.80.Jk, 77.84.Dy, 77.22.Ej

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