A comprehensive review of aging and fatigue phenomena in bulk polycrystalline ferroelectrics is presented. Three material classes are covered, namely the most widely used Pb[Zr1−xTix]O3 (PZT) ceramics lead-free materials, including those based on bismuth sodium titanate Bi1/2Na1/2TiO3 (BNT) alkali niobate [KxNa1−x]NbO3 (KNN). Aging studied poled unpoled states both experimentally theoretically. The variety different loading regimes for includes DC electric field, unipolar, sesquipolar...

An in situ structural description of the origin ferroelectric properties as a function applied electric field E was obtained by synchrotron x-ray diffraction. A setup used to average effects preferred orientation induced strong piezoelectric strain and solve crystal structure field. Hence, we were able describe microscopic macroscopic ferro- most widely material, lead zirconate titanate.

A considerable body of knowledge now exists from studies involving the development lead‐free piezoelectric ceramics and a number high potential alternatives to current lead‐based materials have been identified. Stability under cyclic electric fields is an important property materials. Here, we review research date which shows that fatigue electrical loading prevalent in many ceramic compositions. However, variety compositions mechanisms for behavior these corresponds significant variances...

Temporal behavior of ferroelectric ceramics during the polarization switching cannot be satisfactorily explained by simple Debye or even stretched exponential laws. These materials exhibit rather a wide spectrum characteristic times interpreted different authors as nucleation waiting times, physical reasons for time distribution still remaining unclear. A new model presented here suggests that variance in ferroelectrics originates from random local electric fields due to intrinsic randomness...

The bipolar and unipolar fatigue behavior of the lead‐free piezo‐ ferroelectric 0.94Bi 1/2 Na TiO 3 –0.06BaTiO (94BNT–6BT) was investigated. To obtain a complete profile behavior, both large‐signal (polarization, strain) small‐signal ( d 33 , ɛ ) properties were measured at room temperature. results indicate that material suffers significant degradation in large‐ after cycling, with most occurring first 10 4 cycles test.

The fatigue behavior of the lead‐free piezoelectric Bi 1/2 Na TiO 3 –BaTiO −K 0.5 NbO ( BNT ‐ BT KNN ) under bipolar and unipolar electrical loading is investigated. Special attention paid to effect a decreasing ferroelectric order which was affected by an increase in ‐content. It found that, mainly systems with low ‐content, cycling leads domain wall pinning formation microcracks, while non‐ferroelectric high ‐content can be rationalized repeated field‐induced phase transition occurring...

Abstract Hexagonal manganites, h- R MnO 3 ( =Sc, Y, Ho–Lu), have been intensively studied for their multiferroic properties, magnetoelectric coupling, topological defects and electrically conducting domain walls. Although point strongly affect the conductivity of transition metal oxides, defect chemistry has received little attention. We use a combination experiments first principles electronic structure calculations to elucidate effect interstitial oxygen anions, O i , on electrical...

The role of Fe as an acceptor and Nb a donor in [0.94−x](Bi1/2Na1/2)TiO3–0.06BaTiO3−x (K0.5Na0.5)NbO3 (100xKNN) (x=0.02 0.03) lead-free piezoceramics was investigated. X-ray diffraction analyses show that all the profiles are best-fitted with cubic symmetry where doping tends to induce lattice expansion, while does opposite. strain polarization characteristics enhanced suppressed by dopants, respectively. improvement electrical properties is accompanied stabilization ferroelectric order....

The unipolar fatigue behavior of CaZrO3 and MnO2 co-modified (K,Na,Li)(Nb,Ta)O3 lead-free piezoceramics was investigated systematically. well-known charge agglomeration model is shown to explain the overall changes observed during fatigue, such as development bias field well anisotropy in bipolar strain hysteresis field-dependent dielectric permittivity. In addition, it found that exhibits only small degradation within 3% at amplitude 2 kV/mm up 107 cycles. This exceptionally good resistance...

Piezoceramics of composition 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 demonstrate large recoverable strain at elevated temperature (T > 75 °C), which is absent room temperature. In situ neutron diffraction was used to measure changes in the crystallographic and domain structures during electric field application temperatures ranging from 25 °C 100 °C. Quantitative evaluation ferroelastic volume fraction field-induced phases enabled calculation contribution non-180° switching. The shown be...

High piezoelectric properties are desired for lead‐free materials in consideration as a replacement lead‐based applications. Due to the high coefficient, ( Ba 100− x Ca ) Ti y Zr O 3 BCTZ ceramics have been considered promising alternate material. Here, six compositions were selected based on prediction that all would coefficient at room temperature. The results confirmed exhibit well developed hysteresis loops and large This is due coexistence of several phases where major phase likely be...

Polarization reversal in polycrystalline ferroelectrics is shown to occur via two distinct and sequential domain reorientation steps. This sequence, which cannot be readily discriminated the overall sample polarization, made apparent using time-resolved high-energy x-ray diffraction. Upon application of electric fields opposite initial poling direction, unique significantly different time constants are observed. The first (faster constant) derived by release a residual stress due electrical...

Abstract Total joint replacement implants are generally designed to physically mimic the biological environment ensure compatibility with host tissue. However, implant instability exposes patients long recovery periods, high risk for revision surgeries, and expenses. Introducing electrical stimulation site accelerate healing is promising, but cumbersome nature of wired devices detrimental design. We propose a novel strategy stimulate cells at by utilizing piezoelectric ceramics as sources....

Migration of charged point defects triggered by the local random depolarization field is shown to plausibly explain aging poled ferroelectric ceramics providing reasonable time and acceptor concentration dependences emerging internal bias field. The theory based on evaluation energy caused mismatch polarizations neighbor grains. kinetics charge migration assumes presence mobile oxygen vacancies in material due intentional or unintentional doping. Satisfactory agreement with experiment...

Bipolar electric fatigue in the lead-free material 0.94(Bi1/2Na1/2)TiO3–0.06BaTiO3 (BNT-BT) is investigated throughout first 100 cycles which a strong degradation of macroscopic electromechanical properties observed. The addition 1 mol% CuO successfully stabilizes fatigue-resistant phase and retains initial properties. In order to explain underlying mechanisms, two models are proposed: takes place either due (1) pinning domain walls by defect charges or (2) an field-induced symmetry change...

Acceptor-doped ferroelectrics tend to show pronounced aging behavior. The microscopic effects of are commonly related oxygen vacancies, however, there still open questions with respect their impact on domain wall movements. To elucidate the latter, reverse process de-aging by electric field cycling is investigated here Pb(Zr0.54Ti0.46)O3 doped iron in different concentrations. Measurements hysteretic behavior large-signal parameters, i.e., polarization and strain, as well small-signal...

This article details the influence of zirconium doping on piezoelectric properties and relaxor characteristics 94( Bi 1/2 Na ) TiO 3 –6 Ba ( Zr x Ti 1− O BNT BZT bulk ceramics. Neutron diffraction measurements doped with 0%–15% revealed an electric‐field‐induced transition average crystal structure from pseudo‐cubic to rhombohedral/tetragonal symmetries across entire compositional range. The addition up 10% stabilizes this transition, resulting in saturated polarization hysteresis loops a...

The effect of a uniaxial compressive stress on the properties BZT-BCT samples across morphotropic phase boundary (MPB) is investigated using direct piezoelectric coefficient measurements. In contrast to many lead zirconate titanate compositions, decreases monotonically with increasing and does not show an initial increase or plateau. Electrically softer rhombohedral MPB compositions are found be more susceptible decrease in under pre-stress than tetragonal compositions. Depoling due...