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Size Effects in Barium Titanate Particles and Clusters
Author(s) -
Li Xiaoping,
Shih WeiHeng
Publication year - 1997
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1997.tb03202.x
Subject(s) - barium titanate , tetragonal crystal system , crystallite , particle size , materials science , grain size , enthalpy , particle (ecology) , cluster (spacecraft) , mineralogy , crystallography , condensed matter physics , thermodynamics , chemistry , ceramic , crystal structure , physics , metallurgy , oceanography , computer science , programming language , geology
Clustering has an important effect on the tetragonal‐cubic transformation of barium titanate (BaTiO 3 ) particles. Small particles that would be cubic if they were by themselves can be tetragonal if they are in a cluster. The effects of clustering are shown in the behavior of the c/a ratio of the particles and the enthalpy change, Δ H , of transition as a function of particle size. The c/a ratio and the value of Δ H both decrease at a smaller particle size than those which are observed in samples where clustering is minimal. Our results are consistent with the observation that very small grains in polycrystalline samples can remain tetragonal even though the grain size is so small that it would be cubic if it were an individual particle. The transition temperature, T C , on the other hand, is insensitive to the particle size, which is similar to the observation in polycrystalline BaTiO 3 that T C is insensitive to the grain size. The observed clustering effect is suggested to result from the reduction of depolarization energy of particles in clusters.