The influence of Ni doping on the ferroelectric and dielectric properties have been examined in Sr 0.61 Ba 0.39 Nb 2 O 6 (SBN:61) relaxor crystals. The dopants introduced into SBN:61 crystals promote the switching process by reducing the value of threshold nucleation field, and thus coercive field. We present real-time studies of domain nucleation and growth processes in doped SBN:61 by the nematic liquid crystal (NLC) decoration technique. The broad phase transition and low-frequency dielectric dispersion that are exhibited by doped SBN:61 samples have a strong link to the configuration of the ferroelectrics microdomains, which in turn is strongly determined by Ni ions concentration.

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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.