Octahedral tilt transitions in the relaxor ferroelectric Na1/2Bi1/2TiO3

Meyer, Kai-Christian; Gröting, Melanie; Albe, Karsten

doi:10.1016/j.jssc.2015.03.023

Cited by 21 publications

(15 citation statements)

References 46 publications

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“…Figure gives the formation energies of several tilt defect sizes relative to the energy of the matrix without any defects for an (i) 111‐ordered and an (ii) 001‐ordered system. Both, the red and blue lines depict the T − defects in T + matrices and orthorhombic defects in a rhombohedral matrix from the previous study …”

Section: Resultsmentioning

confidence: 93%

“…The interfaces are only two unit cells wide and strongly affect the energy by the deformation of the oxygen octahedra (see Refs. [] and Figure ). Thus, as already mentioned by Viehland et al, the interaction (or distance) between these regions plays an important role for the phase transformation.…”

Section: Resultsmentioning

confidence: 99%

“…Both, the red and blue lines depict the T À defects in T + matrices and orthorhombic defects in a rhombohedral matrix from the previous study. 48 In Figure 4A, it can be seen that there is a pronounced difference from the red and black (T + in R) lines to the other curves. The difference for the T + cluster in a R matrix to other combinations is similar to the situation of the T À ⇆ O and T À b O phase transformations studied above.…”

Section: Tilt Defect Clustersmentioning

confidence: 88%

“…These findings were confirmed by X-ray diffraction studies, 7,12,13,[18][19][20][21][22][23][24][25] other characterization techniques 13,18,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] and theoretical ab initio studies. [41][42][43][44][45][46][47][48] However, some of the transmission electron microscopy (TEM) studies reported an intermediate orthorhombic phase. [49][50][51][52][53] All proposed structures and phase transitions from the conducted studies are listed in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…In an earlier study, we investigated the size of tilt defect clusters as a possible explanation for these PNRs and found that the lower limit to stabilize these clusters is 40 A. 48 The aspect of nucleation centers of PNRs will be inspected in closer detail at the end of this study.…”

Section: Introductionmentioning

confidence: 99%

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Phase transformations in the relaxor Na_1/2Bi_1/2TiO₃ studied by means of density functional theory calculations

2017

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The relaxor material Na 1/2 Bi 1/2 TiO 3 (NBT) is an important basis for the development of lead-free piezoceramics, but still many features of this material are not well understood. Here, we study the kinetics of phase transformations by octahedral tilts and A-cation displacements in NBT by means of density functional theory calculations, employing ab initio molecular dynamics and nudged elastic band calculations. Our results show that the energetic differences between the low temperature rhombohedral, intermediate orthorhombic and other metastable phases are close to the room temperature thermal energy. Therefore, it is likely that above room temperature, several octahedral tilt patterns are present simultaneously on the local scale, just because of thermal vibration of the oxygen ions. Octahedral tilt transformations and A-cation displacements show similarly high energy barriers, however, since the vibrational frequency of oxygen is higher, tilt transformations occur more frequently. Further, tilt transformations in which the oxygen octahedra get deformed the least are more probable to occur. We also find that the chemical A-cation order affects energy barriers, influences the coupling between rotational and displacive modes and determines the stability of certain octahedral tilt orders. We conclude that the so-called polar nanoregions in this material result from local octahedral tilt transformations and subsequent A-cation displacements, which are driven by thermal vibration and are mediated by the underlying chemical order.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Tilt Defect Clustersmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phase transformations in the relaxor Na_1/2Bi_1/2TiO₃ studied by means of density functional theory calculations

2017

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Giant Capacitive Energy Storage in High‐Entropy Lead‐Free Ceramics with Temperature Self‐Check

Zeng,

Lin,

Shen

et al. 2024

Advanced Materials

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Considering the large demand for electricity in the era of artificial intelligence and big data, there is an urgent need to explore novel energy storage media with higher energy density and intelligent temperature self‐check functions. High‐entropy (HE) ceramic capacitors are of great significance because of their excellent energy storage efficiency and high power density (PD). However, the contradiction between configurational entropy and polarization in traditional HE systems greatly restrains the increase in energy storage density. Herein, the contradiction is effectively solved by regulating the octahedral tilt and cationic displacement in ABO3‐type perovskite HE ceramics, i.e., (1‐x)[0.6(Bi0.47Na0.47Yb0.03Tm0.01)TiO3‐0.4(Ba0.5Sr0.5)TiO3]‐xSr(Zr0.5Hf0.5)O3 (BNYTT‐BST‐xSZH). Combining the tape‐casting process and cold isostatic pressing, the optimal BNYTT‐BST‐0.06SZH ceramic displays a large recoverable energy storage density (10.46 J cm−3) at 685 kV cm−1 and a high PD (332.88 MW cm−3). More importantly, due to Tm/Yb codoping, abnormal fluorescent negative thermal expansion and excellent real‐time temperature sensing are developed, thus the application of fault detection and warning in high‐voltage transmission line systems is conceptualized. This study provides an effective strategy for enhancing the polarization of energy‐storing HE ceramics and offers a promising material for overcoming the problems of insufficient capacitor density and thermal runaway in terminal communication.

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Long-period structural modulation on the global length scale as the characteristic feature of the morphotropic phase boundaries in the Na0.5Bi0.5TiO3 based lead-free piezoelectrics

et al. 2019

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Octahedral tilt transitions in the relaxor ferroelectric Na1/2Bi1/2TiO3

Cited by 21 publications

References 46 publications

Phase transformations in the relaxor Na_1/2Bi_1/2TiO₃ studied by means of density functional theory calculations

Phase transformations in the relaxor Na_1/2Bi_1/2TiO₃ studied by means of density functional theory calculations

Giant Capacitive Energy Storage in High‐Entropy Lead‐Free Ceramics with Temperature Self‐Check

Long-period structural modulation on the global length scale as the characteristic feature of the morphotropic phase boundaries in the Na0.5Bi0.5TiO3 based lead-free piezoelectrics

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Octahedral tilt transitions in the relaxor ferroelectric Na1/2Bi1/2TiO3

Cited by 21 publications

References 46 publications

Phase transformations in the relaxor Na1/2Bi1/2TiO3 studied by means of density functional theory calculations

Phase transformations in the relaxor Na1/2Bi1/2TiO3 studied by means of density functional theory calculations

Giant Capacitive Energy Storage in High‐Entropy Lead‐Free Ceramics with Temperature Self‐Check

Long-period structural modulation on the global length scale as the characteristic feature of the morphotropic phase boundaries in the Na0.5Bi0.5TiO3 based lead-free piezoelectrics

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Product

Resources

About

Phase transformations in the relaxor Na_1/2Bi_1/2TiO₃ studied by means of density functional theory calculations

Phase transformations in the relaxor Na_1/2Bi_1/2TiO₃ studied by means of density functional theory calculations