Electromechanical properties

点击翻译按钮获取中文摘要

The research project is part of a collaborative proposal which aims on the exploration of structure/property relationships of piezoelectric rare earth oxoborates of the composition RX2Z2O(BO3)3 with X, Z = Ca and R = La, Y, Gd, Pr, Nd, Er. The focus is on electromechanicalproperties, because these are not only of basic interest but play a key role for potential applications of the materials as high-temperature piezoelectrics. To this end single crystal piezoelectric and elastic coefficients of selected monoclinic rare earth oxoborates are studied as functions of temperature, frequency and crystals structure / chemical composition employing a broad variety of experimental methods. The fundamental objectives are (i) to develop rules how the macroscopic properties of these crystal species are controlled by structural parameters and (ii) to identify the atomistic processes responsible for the observed discontinuities in the evolution of heat capacity and thermal expansion above about 800 °C. The latter has direct impact on the use of the materials for piezoelectric sensor applications at high temperatures.