In situ TEM observation on the ferroelectric‐antiferroelectric transition in Pb(Nb,Zr,Sn,Ti)O3/ZnO

Abstract

AbstractCeramic composites of (1‐x)Pb0.99{Nb0.02[(Zr0.57Sn0.43)0.937Ti0.063]0.98}O3 (PNZST)/xZnO were recently reported to exhibit exceptionally high pyroelectric coefficients near human body temperature due to the ferroelectric‐antiferroelectric transition of the matrix grains. In the present work, a comparative study is conducted on two composites of x = 0.1 and 0.4 with in situ heating transmission electron microscopy (TEM). The results verify the presence of strain field in the PNZST grain adjacent to a ZnO particle and the stabilized ferroelectric phase at room temperature in the composite of x = 0.1. During heating, the ferroelectric matrix grain transforms to the antiferroelectric phase, contributing to the pyroelectric effect. In the composite of x = 0.4, high‐angle annular dark‐field imaging combined with energy‐dispersive X‐ray spectroscopy reveal the existence of both ZnO and Zn2SnO4. The formation of Zn2SnO4 indicates that Sn in the PNZST matrix grain is selectively extracted, and decomposition of the perovskite phase has taken place. The decomposition products in the form of fine particles are observed to facilitate the nucleation of the antiferroelectric phase and restrict the motion of the phase boundary during heating. The larger amount of ZnO and Zn2SnO4 and the decomposition of the PNZST perovskite phase are suggested to be responsible for the much lower pyroelectric coefficient in the x = 0.4 composite.