Physical properties and radiation tolerance of high-entropy pyrochlores Gd2(Ti0.25Zr0.25Sn0.25Hf0.25)2O7 and individual pyrochlores Gd2X2O7 (X= Ti, Zr, Sn, Hf) from first principles calculations

Liu, Chenguang; Peng, Qing; Shi, Tan; Gao, Fei; Li, Yuhong

doi:10.1016/j.scriptamat.2022.114898

Cited by 12 publications

(2 citation statements)

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“…We also compared the differences between the distorted supercell structures after relaxation optimization with partially disordered state and completely disordered state. [ 28 ] Figure 8a,d show the distorted supercell structures with partially disordered state and completely disordered state after relaxation optimization, respectively. To study the degree of proximity of the A and B sites to each other along the b ‐axis, Figure 8b,e further show the structures along the [100] axis.…”

Section: Resultsmentioning

confidence: 99%

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Ultrahigh Degree of Cationic Disorder, Configurational Entropy in New Type of High‐Entropy Pseudobrookite Phase

Wu,

Zhang,

et al. 2024

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High‐entropy ceramics exhibit various excellent properties owing to their high configurational entropy, which is caused by multi‐principal elements sharing one lattice site. The configurational entropy will further increase significantly if multi‐principal elements randomly share two different lattice sites. For this purpose, pseudobrookite phase containing two cationic lattice sites (A and B sites) is selected, and corresponding high‐entropy pseudobrookite (M2+0.4M3+1.2)Ti1.4O5 is synthesized. Herein, the distribution of the 2‐valent and 3‐valent cations in the A and B sites are analysed in depth. The distance between the A and B sites in the crystal structure models which are constructed by the Rietveld analysis is calculated and defined as distance d. Meanwhile, the atomic column positions in the STEM images are quantified by a model‐based mathematical algorithm, and the corresponding distance d are calculated. By comparing the distance d, it is determine that the 2‐valent and 3‐valent cations are jointly and disorderly distributed in the A and B sites in high‐entropy (M2+0.4M3+1.2)Ti1.4O5. The density functional theory (DFT) simulations also demonstrate that this type of crystal structure is more thermodynamically stable. The higher degree of cationic disorder leads to a higher configurational entropy in high‐entropy (M2+0.4M3+1.2)Ti1.4O5, and endows high‐entropy (M2+0.4M3+1.2)Ti1.4O5 with very low thermal conductivity (1.187−1.249 W m−1 K−1).

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Section: Resultsmentioning

confidence: 99%

“…We also compared the differences between the distorted supercell structures after relaxation optimization with partially disordered state and completely disordered state. [28] Figure 8a,d 8c,e, respectively. The results show a higher degree of the chain-distortion in the structure with completely disordered state.…”

Section: Dft Simulationsmentioning

confidence: 95%