Characterization of new high-temperature piezoelectric single crystals in the system RCa4O(BO3)3 (R = Gd, Sm, La and Y)

压电晶体是现代固态声学和声电子学的关键材料。特别令人感兴趣的是那些在非常高的温度(高达10000摄氏度或更高)下具有合理的压电响应的材料。这种晶体的数量正在消失，研究它们在极高温度下的物理性质是一个相当复杂的实验问题。请注意，高温性能的知识不仅对于可能的应用，而且对于基本了解材料在关键条件下的行为都是重要的。该项目的目标是研究在非常高的温度(约10000摄氏度)下先进的压电晶体的材料参数(弹性、压电和介电常数，以及电阻率)。本文的研究对象是一类新的单斜晶系压电氧硼酸盐，通式为RCa4O(BO3)3(式中R=Gd，Sm，La和Y)。上述单晶在高温下的材料参数几乎是未知的。此外，文献中报道的一些氧硼酸盐单晶的室温材料参数也是相互矛盾的。

Piezoelectric crystals are key materials for modern solid state acoustics and acoustoelectronics. Of particular interest are materials those possess a reasonable piezoelectric response at very high temperatures (up to 10000 C and higher). The number of such crystals is vanishing and the study of their physical properties at very high temperatures is rather complex experimental problem. Notice that the knowledge of the high temperature properties is important not only for possible applications but also for basic understanding of materials behavior under critical conditions. The objective of the project is the study of material parameters (elastic, piezoelectric and dielectric constants, as well as electrical resistivity) of advanced piezoelectric crystals at very high temperatures (about 10000 C). The object under study is a new family of monoclinic piezoelectric oxoborates with the general formula RCa4O(BO3)3 (where R = Gd , Sm, La and Y). Material parameters of above single crystals at high temperatures are practically unknown. Moreover, room temperature material parameters of some oxoborates single crystals reported in literature are contradictory.