Effect of sequential heat impacts on the formation of a stable state of the $x$LPM–$(1-x)$PT multiferroic composites

The effect of thermal cycling and sintering temperature on the chemical and thermodynamic stability of the bulk multiferroic $x$La$_{0.7}$Pb$_{0.3}$MnO$_{3}$–$(1-x)$PbTiO$_{3}$ quasi-ceramic and ceramic composites has been experimentally investigated. It is shown that the limiting temperature of the long-term sample firing should not exceed 1070 K. It has been found that sintering at this temperature and/or short-term exposure of the samples at higher temperatures (up to 1220 K) significantly increase the sample compactness, stabilize the thermal expansion, and enhance the quality of the composites. It has been established that the component grain integrity is violated by shrinkage of the samples and a sharp change in their volume during the phase transition of a ferroelectric component.