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Abstract Relaxor ferroelectrics (RFEs) are being actively investigated for energy‐storage applications due to their large electric‐field‐induced polarization with slim hysteresis and fast energy charging–discharging capability. Here, a novel nanograin engineering approach based upon high kinetic energy deposition is reported, for mechanically inducing the RFE behavior in a normal ferroelectric Pb(Zr0.52Ti0.48)O3(PZT), which results in simultaneous enhancement in the dielectric breakdown strength (EDBS) and polarization. Mechanically transformed relaxor thick films with 4 µm thickness exhibit an exceptionalEDBSof 540 MV m−1and reduced hysteresis with large unsaturated polarization (103.6 µC cm−2), resulting in a record high energy‐storage density of 124.1 J cm−3and a power density of 64.5 MW cm−3. This fundamental advancement is correlated with the generalized nanostructure design that comprises nanocrystalline phases embedded within the amorphous matrix. Microstructure‐tailored ferroelectric behavior overcomes the limitations imposed by traditional compositional design methods and provides a feasible pathway for realization of high‐performance energy‐storage materials.
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The effect of surface termination on dielectric nonlinearity in potassium sodium niobate thin films
Abstract The impact of alkali‐rich and alkali‐depleted surface terminations on dielectric nonlinearity and ferroelectric properties was investigated in sputtered K0.5Na0.5NbO3(KNN) films. For the alkali depleted surface termination, a ∼3 nm thick amorphous interfacial layer was found near the top electrode. The presence of a non‐ferroelectric interfacial layer reduces both the net remanent (Pr) and maximum polarization (Pmax) while increasing the coercive field (Ec) in the KNN films.Pmaxdecreased from 31.5 to 30.3 µC/cm2, likely due to the reduced electric field in the bulk of the film. The influence of the interfacial layer on dielectric properties was evaluated using a capacitor in series model. After removing the effects of the interfacial layer, the Rayleigh coefficientsεinitand α increased by 11 and 47%, respectively. The interfacial layer has more impact on irreversible domain wall motion than on reversible contributions to the relative permittivity. It is believed that this occurs because a higher concentration of defects, such as or , associated with the alkali‐depleted interfacial layer generates internal fields that pin domain walls. Alkali depleted surface terminations also produce a higher pseudo‐activation energy for polarization reversal compared to films with alkali rich terminations, with deeper potential wells in the material's energy landscape.
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- Award ID(s):
- 1841453
- PAR ID:
- 10660384
- Publisher / Repository:
- American Ceramic Society
- Date Published:
- Journal Name:
- Journal of the American Ceramic Society
- Volume:
- 108
- Issue:
- 11
- ISSN:
- 0002-7820
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1111/jace.70084
