I11-High Resolution Powder Diffraction
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Yangda
Dong
,
Yi
Ding
,
Yuqiao
Zhang
,
Ge
Wang
,
Yanghe
Wang
,
Shiyao
Xu
,
Yue
Qin
,
Yuan
Zhang
,
Changjian
Li
,
Xiaohui
Wang
,
Jiagang
Wu
,
Ting
Zheng
Diamond Proposal Number(s):
[27232]
Open Access
Abstract: The sensitivity and reliability of piezoelectric accelerometers heavily rely on the piezoelectric coefficient and temperature stability of their core components. However, the inherent nature of polycrystalline phase boundaries in lead-free piezoceramics poses a significant challenge in simultaneously achieving excellent comprehensive properties. This study proposes a co-fired multilayer piezoceramics architecture to achieve nearly 10-fold increase in piezoelectric coefficient (from 165 pC/N of bulks to 1568 pC/N of multilayer piezoceramics) and significantly enhanced temperature stability in potassium sodium niobate based ceramics, breaking the long-standing trade-off relationship between the two core parameters. The superior temperature stability is achieved by introducing residual thermal stresses in the inner electrode and ceramic layers within the multilayer structure. The introduced internal stress both stabilizes the lower symmetry phases and restrained domain switching. The prototype acceleration sensors were developed and the multilayer piezoceramics device shows a good linearity and higher sensitivity compared to bulk ceramics, with only a slight property fluctuation with temperature increases. This work establishes a feasible strategy for synergistically optimizing piezoelectricity and temperature stability in lead-free ceramics, extending their sensor application for structural health monitoring.
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Apr 2026
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I15-Extreme Conditions
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Diamond Proposal Number(s):
[36011]
Open Access
Abstract: The development of high-performance lead-free piezoelectric materials has gained significant attention due to environmental concerns regarding lead toxicity. In this study, through in-situ poling synchrotron X-ray diffraction (XRD), dielectric spectroscopy, and ferroelectric measurements, we demonstrate an irreversible transition from non-ergodic relaxor behaviour to long-range ferroelectric ordering under applied electric fields in (1-x)BiFeO3 -xSrTiO3 with MnO2 addition (BF-ST-Mn).The optimal composition with x = 0.44 exhibits electrostrain of ~0.10% at 80 kV cm -1 through irreversible pseudo-cubic to rhombohedral structural transformation followed by ferroelectric domain switching. Unlike BF-ST-Nb systems that maintain pseudo-cubic symmetry, the BF-ST-Mn undergo irreversible phase transitions. Synchrotron XRD reveals initial structural transformation during the first electrical cycle, followed by domain switching in subsequent cycles. It provides promising pathways for lead-free actuator applications requiring high electrostrain at moderate driving fields.
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Jan 2026
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[34380]
Open Access
Abstract: The structural evolution and electrical behaviour of (1−x) NaNbO3-xCaTiO3 (NN-CT) ceramics were investigated in this study. X-ray diffraction and full-pattern Rietveld refinement confirm that CT incorporation disrupts the long-range antipolar orthorhombic Pbcm phase. The dielectric permittivity peak shifts to lower temperatures as the CT concentration increases. The highest permittivity of 2365 was obtained for x = 0.15 at room temperature. Synchrotron X-ray scattering coupled with pair distribution function (PDF) analysis reveals the existence of a short-range ordered polar orthorhombic P21ma (Q) phase with a correlation length of approximately 5 nm. A slim ferroelectric polarisation-electric field (P-E) loop, consistent with short-range ordered behaviour, was obtained in the NN-0.15CT, yielding an enhanced recoverable energy density by over 300 % at 150 kV cm−1 compared to pure NN. These findings establish the role of CT doping in modifying structural and dielectric properties, contributing to the understanding of crystal symmetry evolution and its impact on the dielectric response of this promising, environmentally friendly lead-free perovskite oxide for high-performance dielectric applications.
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Oct 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Weichen
Zhao
,
Zhaobo
Liu
,
Diming
Xu
,
Ge
Wang
,
Da
Li
,
Jinnan
Liu
,
Zhentao
Wang
,
Yan
Guo
,
Jiajia
Ren
,
Tao
Zhou
,
Lixia
Pang
,
Hongwei
Yang
,
Wenfeng
Liu
,
Houbin
Huang
,
Di
Zhou
Diamond Proposal Number(s):
[34380]
Open Access
Abstract: Multilayer ceramic capacitors are cornerstone components of modern electronic systems. Yet ensuring reliability under demanding operational conditions, such as elevated temperatures and prolonged cycling, while achieving holistic optimization of recoverable energy density and efficiency remains a significant challenge. Herein, we implement a polar glass state strategy that catalyzes a profound enhancement in energy storage performance by modulating dynamic and thermodynamic processes. This approach minimizes hysteresis loss and improves breakdown strength through hierarchical structural engineering, disrupting nano-domains and refining grains. An ultra-high recoverable energy density of 22.92 J cm−3 and exceptional efficiency of 97.1%, accompanied with state-of-the-art high-temperature stability are achieved in Bi0.5Na0.5TiO3-based multilayer ceramic capacitors. This strategy promises to be a transformative blueprint for developing cutting-edge dielectric capacitors for high-temperature applications.
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Jul 2025
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I15-Extreme Conditions
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Diamond Proposal Number(s):
[31608]
Open Access
Abstract: Electric field-induced phase transition behaviour, extensively studied in perovskite-structured ceramics, has not been previously reported in unfilled tetragonal tungsten bronze (TTB) structured ceramics. In this work, we present the first investigation of electric field-induced phase transitions in high entropy designed unfilled TTB structured Ca0.25Sr0.25Ba0.25Pb0.25Nb2O6 (CSBP) ceramics using dielectric and ferroelectric characterization techniques. The findings reveal that field-induced polarization in the CSBP ceramics evolve from irreversible to reversible with increasing temperature. Furthermore, relaxor ferroelectric behaviour was observed in the ceramics, attributed to the A-site cation disorders in the unfilled TTB structure, facilitated by the high entropy design. The absence of non-180° domain switching was indicated by microstructural observations and analysis of the strain-electric field (S-E) response. In-situ poling synchrotron studies and experimental S-E response measurements revealed an electrostrictive behaviour characterized by an electrostrain not originating from macroscopic structural transformations or long-range domain switching but more likely contributed by the reorientation of polar nanoregions. The results obtained provide a foundation for future studies investigating the electric field-induced phase transition and domain switching behaviour in the unfilled TTB structured ceramics.
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Nov 2024
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[27232]
Open Access
Abstract: Uncovering lead-free materials with an exceptionally high recoverable energy density is vital for the creation of future pulse power capacitors. This study determined that introducing Tungsten (W) and Tantalum (Ta) into the Nb-site of AgNbO3 lead-free antiferroelectric ceramics, while offsetting this with vacancies at the Ag-site, can effectively maintain the electrical homogeneity. Additionally, employing this co-doping approach can secure the antiferroelectric phases by lowering the necessary temperatures for M1-M2 and M2-M3 phase transitions. This may prove advantageous in the creation of novel AgNbO3-based energy storage ceramics. The use of in-situ high-resolution synchrotron powder x-ray diffraction (SPXD) at varying temperatures revealed for the first time that in 10 at% W doped AgNbO3, the M1 and M2 phases in the temperature range of −193 to ∼150 °C are more appropriately fitted as the non-polar Pbcm space group, whereas the M3 phase aligns with the mixed of non-polar Pbcm and polar Pmc21 space groups.
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Dec 2023
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I15-1-X-ray Pair Distribution Function (XPDF)
I15-Extreme Conditions
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Ge
Wang
,
Tengfei
Hu
,
Wenxuan
Zhu
,
Zhilun
Lu
,
Annette
Kleppe
,
Maria
Diaz Lopez
,
Antonio
Feteira
,
Derek C.
Sinclair
,
Zhengqian
Fu
,
Houbing
Huang
,
Dawei
Wang
,
Ian M.
Reaney
Diamond Proposal Number(s):
[21714, 27500]
Abstract: For the first time, the origin of large electrostrain in pseudocubic
BiFeO
3
-based ceramics is verified with direct structural evidence backed by appropriate simulations. We employ advanced structural and microstructural characterizations of
BiFeO
3
-based ceramics that exhibit large electrostrain (
>
0.4
%
) to reveal the existence of multiple, nanoscale local symmetries, dominantly tetragonal or orthorhombic, which have a common, averaged direction of polarization over larger, meso- or microscale regions. Phase-field simulations confirm the existence of local nanoscale symmetries, thereby providing a new vision for designing high-performance lead-free ceramics for high-strain actuators.
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Feb 2023
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I15-Extreme Conditions
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Diamond Proposal Number(s):
[21714]
Open Access
Abstract: The origin of the large electrostrain in BiFeO3-BaTiO3 (BF-BT) ceramics is controversial and has been attributed to either a field-induced transition to a long-range ferroelectric (FE) state or to multi-symmetry, polar nanoregions within a pseudocubic matrix whose vectors approximately align with the direction of the applied field. The (1-x)BiFeO3-xSrTiO3 (BF-xST) solid solution is structurally and microstructurally similar to BF-BT and provides a further case study to assess the origin of electrostrain. In BF-xST, electrostrain is optimised at x = 0.4 (0.15%) which zero field, room temperature full-pattern X-ray diffraction (XRD) Rietveld refinement and scanning/transmission electron microscopy suggest is composed of 15% rhombohedral (R) cores, surrounded by 85% pseudocubic (PC) shells. In-situ poling synchrotron XRD revealed that all peaks remained singlet and exhibited no change in full width half maximum up to 100 kV cm-1, confirming the absence of long-range FE order and the retention of short-range polar order, despite the large applied field. Strain anisotropy (calculated from individual peaks) of ε220 > ε111 > ε200 and the associated strain orientation distribution however, indicate the existence of local orthorhombic (O), rhombohedral (R) and tetragonal (T) symmetries. The data therefore imply the existence under poling of multi-symmetry polar nanoregions in BF-0.4ST rather than a long FE phase, supporting the model described by Wang and co-workers (2019) for BF-BT compositions.
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May 2021
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John
Irvine
,
Jennifer
Rupp
,
Gang
Liu
,
Xiaoxiang
Xu
,
Sossina M
Haile
,
Xin
Qian
,
Alem
Snyder
,
Robert
Freer
,
Dursun
Ekren
,
Stephen
Skinner
,
Ozden
Celikbilek
,
Shigang
Chen
,
Shanwen
Tao
,
Tae Ho
Shin
,
Ryan
O'Hayre
,
Jake
Huang
,
Chuancheng
Duan
,
Meagan
Papac
,
Shuangbin
Li
,
Andrea
Russell
,
Veronica
Celorrio
,
Brian
Hayden
,
Hugo
Nolan
,
Xiubing
Huang
,
Ge
Wang
,
Ian
Metcalfe
,
Dragos
Neagu
,
Susana Garcia
Martin
Open Access
Abstract: Inorganic perovskites exhibit many important physical properties such as ferroelectricity, magnetoresistance and superconductivity as well their importance as Energy Materials. Many of the most important energy materials are inorganic perovskites and find application in batteries, fuel cells, photocatalysts, catalysis, thermoelectrics and solar thermal. In all these applications, perovskite oxides, or their derivatives offer highly competitive performance, often state of the art and so tend to dominate research into energy material. In the following sections, we review these functionalities in turn seeking to facilitate the interchange of ideas between domains. The potential for improvement is explored and we highlight the importance of both detailed modelling and in situ and operando studies in taking these materials forward.
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May 2021
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I15-Extreme Conditions
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Hongfen
Ji
,
Dawei
Wang
,
Weichao
Bao
,
Zhilun
Lu
,
Ge
Wang
,
Huijing
Yang
,
Ali
Mostaed
,
Linhao
Li
,
Antonio
Feteira
,
Shikuan
Sun
,
Fangfang
Xu
,
Dejun
Li
,
Chao-Jie
Ma
,
Shi-Yu
Liu
,
Ian M.
Reaney
Diamond Proposal Number(s):
[21714]
Abstract: Dense pseudocubic 0.62Na0.5Bi0.5TiO3-0.3Sr0.7Bi0.2TiO3-0.08BiMg2/3Nb1/3O3 (NBT-SBT-0.08BMN) ceramics with excellent recoverable energy density, Wrec = 7.5 J/cm3, and conversion efficiency, η = 92%, were synthesized. Large electric breakdown strength was facilitated by electrical homogeneity, high resistivity and large activation energy (1.86 eV). Transmission electron microscopy identified the presence of polar nano-regions (PNRs) in a matrix of short coherence in-phase and antiphase octahedral tilting. Combining polar and tilt order restricted the crystal classes of PNRs to tetragonal, orthorhombic and monoclinic. Using these symmetries, the enhancement of polarization was explained using Landau-Devonshire phenomenology and percolation theory. Octahedral tilting and introduction of larger B-site ions (Mg2+, Nb5+) inhibited long range polar coupling, minimizing strain and maximizing η. Wrec was further improved to 18 J/cm3 (>1000 kV/cm) in multilayers whose properties were stable from 0.01–100 Hz, from 20°C–160°C and up to 106 cycles, attractive for pulsed power applications and power electronics.
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Jan 2021
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