Realizing Negative Thermal Expansion over an Extended Temperature Range in PbTiO3-Based Perovskites (IMAGE)
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A novel PbTiO3-based perovskite system, (1-x)PbTiO3-xBiYbO3, synthesized using a distinctive high-pressure and high-temperature technique was reported. The system exhibits an unusual enhanced tetragonalities compared to pristine PbTiO3 (c/a = 1.064). Consequently, NTE over an extended temperature range has been realized in 0.95PbTiO3-0.05BiYbO3 ( = -2.18 ´ 10-5/K, 300 - 820 K) and 0.90PbTiO3-0.10BiYbO3 ( = -1.85 ´ 10-5/K, 300 - 850 K), respectively, when compared to that of pristine PbTiO3 ( = -1.99 ´ 10-5/K, 300 - 763 K). Our experimental and theoretical studies indicate that the improved tetragonalities and expanded NTE temperature range result from stronger Pb/Bi-O and Ti/Yb-O bond strengths, and an asymmetrically distributed charge density. The present study presents a new instance of NTE across a broad temperature range, highlighting its potential as an effective thermal expansion compensator.
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Journal of Advanced Ceramics, Tsinghua University Press
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