Temperature dependence of mode coupling effect in piezoelectric vibrator made of 001_c-poled Mn-doped 0.24PIN-0.46PMN-0.30PT ternary single crystals with high electromechanical coupling factor

The influence of temperature on mode coupling effect in piezoelectric vibrators remains unclear. In this work, we discuss the influence of temperature on two-dimensional (2D) mode coupling effect and electromechanical coupling coefficient of cylindrical 001_c-poled Mn-doped 0.24PIN-0.46PMN-0.30PT piezoelectric single-crystal vibrator with an arbitrary configuration ratio. The electromechanical coupling coefficient k_t decreases with temperature increasing, whereas k₃₃ is largely invariant in a temperature range of 25 ℃-55 ℃. With the increase of temperature, the shift in the ‘mode dividing point’ increases the scale of the poling direction of the piezoelectric vibrator. The temperature has little effect on coupling constant Γ. At a given temperature, the coupling constant Γ of the cylindrical vibrator is slightly greater than that of the rectangular vibrator. When the temperature changes, the applicability index (M) values of the two piezoelectric vibrators are close to 1, indicating that the coupling theory can be applied to piezoelectric vibrators made of late-model piezoelectric single crystals.