Abstract

HUANOSTA-GUTIERREZ, Areli et al. Determinación de la temperatura de transición ferroeléctrica por efecto fotoacústico: La fenomenología involucrada. Rev. LatinAm. Metal. Mater. [online]. 2009, vol.29, n.1, pp.23-31. ISSN 0255-6952.

As far as we know, for the first time it is here stated the appropriate experimental conditions and offered an explanation to the mechanism for the determination of ferroelectric transition temperatures by photoacoustic effect. The explanation involves the analysis of the temperature dependence of an intrinsic parameter of the material: compressibility. At a constant temperature, ΔV/Δp determines the compressibility of a material, but this last ratio is also involved in the fotoacoustic effect, these facts are used here to achieve the analysis of experimental results. The found relation explains the behavior of a correlation function constructed with the response of photoacoustic successive events. The photoacoustic effect is used here to obtain T_c in BaTiO₃. Ferroelectric transition temperatures determined by the permittivity behavior, investigated as a function of temperature, are perfectly compatible with the obtained via photoacoustic experiments, as shown in this work. However, there is an advantage when photoacoustic is used; results are not affected by the presence of high conductivity components, as happens with permittivity determinations. From our point of view, the interpretation given here can be applied to every phase transition that involves a change in compressibility.

Keywords : Photoacoustic effect; Compressibility; Ferroelectric; Transition temperature.