Ergodic-nonergodic relaxor behavior, recoverable energy storage density, and dynamic hysteresis scaling in NKBT ferroelectrics

The present study examined the scaling behavior of the room temperature ferroelectric hysteresis and switching current curves for lead-free and eco-friendly K+1 rich NBT (Na0.5Bi0.5TiO3) -based compositions. The scaling behavior between the logarithms of the hysteresis area and the logarithm of the amplitude (E) of the field evolve in three regions for all the compositions. Three different stages have been described in detail with the amplitude of the electric field (E). The domain dynamic behavior in different regions has been revealed with the help of the power scaling law. Based on the shape, size, and value of the Polarization (P), switching current (I), and, Strain curve (S), the evolution of relaxor phases and domain switching mechanism were studied for the K+1—rich substituted NBT. The recoverable energy storage density (Wrec) of the material is also influenced by the shape of the P–E loop and analyzed by scaling of Wrec. Interestingly, three regions had been observed in the ln Wrecvs ln E graph for the pinched type P–E loop, whereas the graph showed linear relation for the slanted type of loop. Although all of the compositions in this study exhibited good Wrec, the optimum Wrec was found to be 0.5 J/cm3 for NKBT-30, which showed a breakdown strength of 79 kV/cm. We also established a complete scenario for the NKBT series in terms of the evolution of relaxor nature based on the ferroelectric properties and their applications