优秀的高机电耦合器件需要较优秀的温度稳定性在先前的研究中显示15R陶瓷的d33具有很好的温度稳定性主要是相和畴结构的复合作用导致的。图4a为未极化极化后的15R15T的εr与温度的关系图从图中可以看到不管是否极化15T陶瓷的Tm与15R陶瓷相近这与0组分陶瓷的变化不太一致主要原因是15组分陶瓷的弛豫性很强其Tm的附近相变为弥散型相变故NN籽晶模板引入后带来的组分轻微偏差或者显微结构影响不足以引起T

Excellent high electromechanical coupling devices require good temperature stability. Previous research has shown that the d33 of 1.5R ceramics has good temperature stability, mainly due to the composite effect of phase and domain structure. Figure 4a shows the relationship between εr and temperature of 1.5R/1.5T ceramics before/after polarization. It can be seen from the figure that regardless of polarization, the Tm of 1.5T ceramics is similar to that of 1.5R ceramics. This is different from the change of 0-component ceramics. The main reason is that the 1.5-component ceramics have strong relaxation properties, and the phase transition near Tm is a diffuse phase transition, so the slight deviation of component or microstructure caused by NN seed crystal template is not enough to cause significant changes in Tm. Due to the effect of interface stress/piezoelectric composite effect caused by texture process, the εr of unpolarized 1.5T ceramics is smaller than that of 1.5R ceramics. This phenomenon can be more clearly seen in polarized 1.5T and 1.5R ceramics. Interestingly, at low temperatures (less than 0 ℃), the dielectric constants of polarized 1.5T and 1.5R ceramics are almost the same. As the temperature rises, the difference in dielectric constant increases, and the maximum value appears near Tm. After the temperature exceeds Tm, the difference in dielectric constant gradually decreases, and it remains the same after 175 ℃. These three temperatures are the temperature at which RFNs appear, the temperature at which all are converted to RFNs, and the temperature at which they are converted to PNRs, indicating that the dielectric constant of ceramics with RFNs is more easily suppressed by the texture process after polarization. The reason for this result may be that at low temperatures, when all domain structures are FMs, the domain structure has already flipped to a certain direction after polarization, and it is difficult to flip back, so the interface stress/piezoelectric composite effect cannot have too much influence on the dielectric response. RFNs come from the destroyed FMs, and their content gradually increases as the temperature rises. Some RFNs will flip back after the voltage is removed, and are more susceptible to the influence of interface stress/piezoelectric composite response. PNRs are too small to be constrained by the interface stress/piezoelectric composite effect, resulting in the disappearance of the interface stress/piezoelectric composite effect, and the εr of unpolarized 1.5R and 1.5T ceramics have already coincided before this temperature. This also confirms that the use of texture process can effectively reduce the dielectric constant of ceramics, thus obtaining a higher quality factor, which is more suitable for relaxation piezoelectric ceramics with RFNs.