Domain nucleation and growth in relaxor-ferroelectric Sr_0.58Ba_0.42Nb₂O₆doped with chromium and ytterbium

Abstract

We present real-time studies of domain nucleation and growth processes in Sr0.58Ba0.42Nb2O6 (SBN:58) crystals doped with Cr and Yb ions, by the nematic liquid crystal (NLC) decoration technique. Our results show that the polarization reversal in doped SBN crystals is strongly affected by a random-field environment related to the relaxor properties of this material. An important result is the increase of the relative contribution of transient nucleation to polarization reversal in a constant electric field application. The sideways domain wall motion proceeds through a pinning–depinning mechanism. This is reflected in a very fine, irregular domain structure during polarization reversal. Registration of domain dynamics in conjunction with the switching current recording have shown that there are slow switching regions that do not contribute to the switching current signals, even under electric field exceeding the coercive field. The kinetics of polarization in SBN:58 doped crystals is described with a stretched exponential function.

Effect of Ni doping on ferroelectric and dielectric properties of strontium barium niobate crystals

“…In the PFM experiment conditions, the electric field is strongly localized and inhomogeneous. A microscale domain state in SBN crystals was observed by electrooptic imaging microscope [18,19] and the NLC method [20,21]. The NLC method involves averaging over macroscopic scale and this enables as to correlate the domain structure dynamics with the macroscopic characterization techniques; switching current, hysteresis loop, and dielectric permittivity measurements.…”

Ferroelectric and dielectric characterization studies on relaxor- and ferroelectric-like strontium-barium niobates

“…Mostly, highresolution domain structure studies (nanoscale domains) have been performed for a congruently melting composition Sr 0.61 Ba 0.39 Nb 2 O 6 (SBN:61) by piezoresponse force microscopy (PFM) [3][4][5][6][7][8]. The microscale domain structure kinetics in SBN:61 was investigated using an electro-optic imaging microscope [9,10] and NLC method [11][12][13]. The observed specific features of the switching process were accounted for freezing or pinning domain walls connected with disordered structure of SBN crystals.…”