Novel 0.38BMT–0.62PbT single crystals with high T _c , as well as good and temperature-stable piezoelectric properties have been grown by a flux method.

A decrease of piezoelectric properties in the fabrication of ultra-small Pb(Mg_1/3Nb_2/3)–x%PbTiO3 (PMN–x%PT) for high-frequency (>20 MHz) ultrasonic array transducers remains an urgent problem. Here, PMN–31%PT with micron-sized kerfs and high piezoelectric performance was micromachined using a 355 nm laser. We studied the kerf profile as a function of laser parameters, revealing that micron-sized kerfs with designated profiles and fewer micro-cracks can be obtained by optimizing the laser parameters. The domain morphology of micromachined PMN–31%PT was thoroughly analyzed to validate the superior piezoelectric performance maintained near the kerfs. A high piezoresponse of the samples after micromachining was also successfully demonstrated by determining the effective piezoelectric coefficient (d₃₃*~1200 pm/V). Our results are promising for fabricating superior PMN–31%PT and other piezoelectric high-frequency (>20 MHz) ultrasonic array transducers.

The challenge of achieving micro kerf (0.72). The transducer exhibited an average center frequency of 29.76 MHz, an average -6 dB bandwidth of 90.5%, and a high peak-to-peak voltage of 746±87 mV at 0 dB gain. We provided valuable insights into the complicated ablation mechanisms generated by ultrafast lasers, which are critical for determining optimal settings, as well as introducing more accessible approaches for producing high-performance PMN–PT composite transducers.

The temperature-dependent characterization of full tensor properties of single-domain relaxor-based single crystals (SCs) is important for understanding the influence of temperature on the properties of their multidomain SCs. However, no relevant results have been published because characterization is difficult to achieve using the traditional electric resonance method. In this Letter, the temperature-dependent elastic and piezoelectric properties of single-domain [111]c poled Mn-doped 28Pb(In1/2Nb1/2)O3-43Pb(Mg1/3Nb2/3)O3-29PbTiO3 SCs were investigated in the range of 20–80 °C by resonant ultrasound spectroscopy (RUS) using a rectangular parallelepiped sample. The temperature-dependent dielectric constants were calculated from the measured capacitances of the sample. The results are self-consistent because they were obtained from the same sample. The elastic constants obtained using the ultrasonic pulse-echo method agree closely with those obtained using RUS. Moreover, the experimental results of electric impedance spectrum agree closely with those simulated using the material constants characterized herein, indicating that the characterization is reliable.

A peculiar temperature-stable piezoelectric performance and strong self-poling effect was observed in tetragonal phase ferroelectric single crystals 0.38Bi(Mg_1/2Ti_1/2)O₃–0.62PbTiO₃. The piezoelectric coefficient d₃₃ of the as-prepared sample with self-poling is 158 pC N⁻¹, and it is as high as 75% of the value produced by an external electric field. The internal electric field E_i exists and the value is 4.34 kV cm⁻¹ at the applied electric field of 40 kV cm⁻¹. The defect dipoles pin on the ferroelectric domains and stabilize the piezoelectric properties and the piezoelectric coefficient d₃₃ at room temperature is nearly unchanged until the annealing temperature up to 800 °C, which is much higher than the Curie temperature T_c ∼ 520 °C.