Quantitative analysis of atomic-scale local lattice distortions in high-entropy fluorite oxide (Zr0·2Ce0.2Hf0.2Y0·2Al0.2)O2-δ

Wen, Yu; Liu, Yufu

doi:10.1016/j.ceramint.2023.05.081

Cited by 8 publications

(1 citation statement)

References 29 publications

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“…Here, lattice distortion is generated from coordination polyhedra deviating from ideality to become irregular polyhedral. In HECs, large deviations from ideality have been observed in perovskites [9,33], fluorites [36], and rocksalts [37] and is expected to exist in a number of other systems. Cation coordination polyhedra around central O anions have been shown to be severely distorted due to the cations at the vertices of any polyhedron being comprised of dissimilar cationic species.…”

Section: The Advantages Of Chemical Complexitymentioning

confidence: 99%

High entropy ceramics for applications in extreme environments

Ward,

Wilkerson,

Musicó

et al. 2024

J. Phys. Mater.

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Compositionally complex materials have demonstrated extraordinary promise for structural robustness in extreme environments. Of these, the most commonly thought of are high entropy alloys, where chemical complexity grants uncommon combinations of hardness, ductility, and thermal resilience. In contrast to these metal-metal bonded systems, the addition of ionic and covalent bonding has led to the discovery of high entropy ceramics. These materials also possess outstanding structural, thermal, and chemical robustness but with a far greater variety of functional properties which enable access to continuously controllable magnetic, electronic, and optical phenomena. In this experimentally focused perspective, we outline the potential for high entropy ceramics in functional applications under extreme environments, where intrinsic stability may provide a new path toward inherently hardened device design. Current works on high entropy carbides, actinide bearing ceramics, and high entropy oxides are reviewed in the areas of radiation, high temperature, and corrosion tolerance where the role of local disorder is shown to create pathways toward self-healing and structural robustness. In this context, new strategies for creating future electronic, magnetic, and optical devices to be operated in harsh environments are outlined.

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Section: The Advantages Of Chemical Complexitymentioning

confidence: 99%

High entropy ceramics for applications in extreme environments

Ward,

Wilkerson,

Musicó

et al. 2024

J. Phys. Mater.

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Tuning the Spin Transition and Carrier Type in Rare‐Earth Cobaltates via Compositional Complexity

Zhang,

Oh,

Choi

et al. 2024

Advanced Materials

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There is growing interest in material candidates with properties that can be engineered beyond traditional design limits. Compositionally complex oxides (CCO), often called high entropy oxides, are excellent candidates, wherein a lattice site shares more than four cations, forming single‐phase solid solutions with unique properties. However, the nature of compositional complexity in dictating properties remains unclear, with characteristics that are difficult to calculate from first principles. Here, compositional complexity is demonstrated as a tunable parameter in a spin‐transition oxide semiconductor La1− x(Nd, Sm, Gd, Y)x/4CoO3, by varying the population x of rare earth cations over 0.00≤ x≤ 0.80. Across the series, increasing complexity is revealed to systematically improve crystallinity, increase the amount of electron versus hole carriers, and tune the spin transition temperature and on‐off ratio. At high a population (x = 0.8), Seebeck measurements indicate a crossover from hole‐majority to electron‐majority conduction without the introduction of conventional electron donors, and tunable complexity is proposed as new method to dope semiconductors. First principles calculations combined with angle resolved photoemission reveal an unconventional doping mechanism of lattice distortions leading to asymmetric hole localization over electrons. Thus, tunable complexity is demonstrated as a facile knob to improve crystallinity, tune electronic transitions, and to dope semiconductors beyond traditional means.

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