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Colossal Negative Thermal Expansion in Electron‐Doped PbVO 3 Perovskites
Author(s) -
Yamamoto Hajime,
Imai Takashi,
Sakai Yuki,
Azuma Masaki
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201804082
Subject(s) - negative thermal expansion , thermal expansion , tetragonal crystal system , crystallite , materials science , perovskite (structure) , anisotropy , condensed matter physics , doping , analytical chemistry (journal) , crystallography , chemistry , crystal structure , composite material , optics , metallurgy , physics , chromatography
Colossal negative thermal expansion (NTE) with a volume contraction of about 8 %, the largest value reported so far for NTE materials, was observed in an electron‐doped giant tetragonal perovskite compound Pb 1− x Bi x VO 3 ( x =0.2 and 0.3). A polar tetragonal ( P 4 mm ) to non‐polar cubic structural transition took place upon heating. The coefficient of thermal expansion (CTE) and the working temperature could be tuned by changing the Bi content, and La substitution decreased the transition temperature to room temperature. Pb 0.76 La 0.04 Bi 0.20 VO 3 exhibited a unit cell volume contraction of 6.7 % from 200 K to 420 K. Interestingly, further gigantic NTE of about 8.5 % was observed in a dilametric measurement of a Pb 0.76 La 0.04 Bi 0.20 VO 3 polycrystalline sample. The pronounced NTE in the sintered body should be attributed to an anisotropic lattice parameter change.