Electric‐field induced phase transition and fatigue behaviors of (Bi_0.5+x/2Na_0.5‐x/2)_0.94Ba_0.06Ti_1‐xFe_xO₃ ferroelectrics

Abstract

The dielectric, piezoelectric properties, and fatigue behaviors of stoichiometric (Bi0.5+x/2Na0.5‐x/2)0.94Ba0.06Ti1‐xFexO3 (BNBT‐xFe) ferroelectrics are investigated. Fe substitution leads to the downward shift of the ferroelectric‐relaxor transition temperature (TF‐R) and increase in strain. Meanwhile, fatigue behaviors of the modified ceramics are significantly enhanced. Ex situ X‐ray diffraction and transmission electron microscopy reveal microscopic mechanism for polarization fatigue on different compositions. The fatigue‐free behavior of ferroelectric BNBT‐0.03Fe is not only attributed to a mechanism involving the formation of defect dipoles, which reduces the pinning effect of migratory oxygen vacancies on domain walls, but is also connected to the decrease in easily suppressed field‐induced ferroelectric tetragonal phase. While for ergodic relaxor BNBT‐0.09Fe, the absence of domain wall contributes to the good fatigue resistance behavior. Interestingly, electric cycling results in an increased fraction of relaxor phase, accompanying by the increase in the total strain and decrease in remnant polarizations.

A Review of MEMS Scale Piezoelectric Energy Harvester

“…It should be noted that doping could increase the Curie temperature or the quality of grain growth, but d 33 and K p would decrease slightly [37,38]. In 2016, Shi et al [39] studied the effect of Fe on the piezoelectric properties and fatigue behavior of (Bi 0.5+x/2 Na 0.5−x/2 ) 0.94 -Ba 0.06 Ti 1−x Fe x O 3 (BNBT-xFe). They found that the induction of Fe in the electric field resulted in the decrease in the ferroelectric-relaxor transition temperature, but the strain would increase.…”

Electric field effect on the microstructure and properties of Ba0.9Ca0.1Ti0.9Zr0.1O3 (BCTZ) lead-free ceramics

“…The electric field makes the ferroelectric-ferroelastic domain walls move, developing a preferred orientation on the poled ceramics manifested in the diffraction pattern as alternation in the ratio of the intensities of the Bragg profiles 17,21 . Besides, some lead-free materials, which in the unpoled state present a coexistence of crystal symmetries, undergoes a field-induced phase transition to the most ferroelectrically distorted one, at the expenses of the weakly polar ones, that can be analyzed by X-ray diffraction [22][23][24] . Such a field-induced phase transition provides an additional contribution to the piezoelectric effects presented by these lead-free ceramics.…”

Ultrafast discharge properties and enhanced energy density in lead‐free NaNbO3‐based relaxor ferroelectric ceramics

“…Figure 5B presents the current-electric field (I-E) curves, with the prominent current peak at x = 0.15 when the electric field reaches 50 kV/cm, suggesting a transition from ferroelectric to relaxor ferroelectric state. 29 The current peaks decrease and diffuse gradually due to the introduction of BZTBT induces the formation of PNRs within the ferroelectric matrix, which can rapidly respond to applied electric fields. Figure 5C,D shows the relationship among P, W, and η with the xBZTBT, although the W total exhibits a gradual decrease due to the reduction of P max , the W rec reaches a peak of 1.51 J/cm 3 at x = 0.25, which is attributed to the continuous increase in η stemming from the reduction in P r .…”

“…Both the P r and P max show a decreasing trend with increasing content of BZTBT. Figure 5B presents the current‐electric field ( I–E ) curves, with the prominent current peak at x = 0.15 when the electric field reaches 50 kV/cm, suggesting a transition from ferroelectric to relaxor ferroelectric state 29 . The current peaks decrease and diffuse gradually due to the introduction of BZTBT induces the formation of PNRs within the ferroelectric matrix, which can rapidly respond to applied electric fields.…”