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Photoacoustic study of phase transition in Aurivillius type ceramics

Abstract:

A correlated photoacoustic signal analysis was used for the study of the phase transition in Aurivillius ceramics. Four different ceramic compositions were studied: Bi 4 Ti 3 O 12 (BIT), PbBi 4 Ti 4 O 15 (PBIT), Pb 2 Bi 4 Ti 5 O 18 (P2BIT) and Pb 3 Bi 4 Ti 6 O 21 (P3BIT). The signal analysis of the normalised correlation allowed us to be sure of thermal stability of the material during the measurement. A widening of the acoustic signal in the phase transition region was observed as a function of the increase of the integration factor of the Aurivillius ceramics. This increment of the integration factor produces a structural change that modified the ferroelectric-paraelectric transition from normal ferroelectric to a relaxor type transition. The photoacoustic study reveals the appearance of thermoelastic phenomena in addition of the phase transition. © 2002 Taylor & Francis.