Yaoyao Zhang

Enhanced piezoelectric and ferroelectric properties in Mn-doped Na0.5Bi0.5TiO3–BaTiO3 single crystals

High piezoelectric and ferroelectric properties have been found in Mn-doped Na0.5Bi0.5TiO3–BaTiO3 single crystals, which were grown by a top-seeded solution method. The electrical resistivity, dielectric constant, and ferroelectric and piezoelectric properties were all found to be notably enhanced by Mn. The piezoelectric constant d33 and electromechanical coupling coefficients kt and k31 were found to be as high as 483 pC/N, 0.56, and 0.40, respectively. These values are much higher than those previously reported for Pb-free piezoelectric crystals, demonstrating the real potential for alternative lead-free systems for sensor and piezoelectric applications.

Piezoelectric energy harvesting using shear mode 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 single crystal cantilever

In this letter we presented a cantilever beam used for vibration energy harvesting based on shear mode 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 single crystal. The working principle of the device was inferred and the factors influencing the output were obtained using an analytical method. The electrical properties under different conditions were studied systematically. Under a cyclic force of 0.05 N (peak value), a peak voltage of 91.23 V, maximum power of 4.16 mW were measured at 60 Hz with a proof mass of 0.5 g. The results demonstrate the potential of the device in energy harvesting applied to low-power portable electronics and wireless sensors.

Shear-mode piezoelectric properties of ternary Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystals

A systematic study of the optimized orientation and temperature dependence of shear-mode piezoelectric properties for ternary Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT or PIMNT) piezocrystals was carried out. It was found that [111]-poled samples presented the best shear piezoelectric properties when driving along [11¯0] (the thickness direction). The electromechanical coupling coefficient k15 and piezoelectric coefficient d15 and g15 were found to be 96.4%, 5966 pC/N, and 0.047 Vm/N, respectively, for optimum-cut samples with platinum (Pt) electrode. Besides, the maximum service temperature for shear mode is around 105 °C, which is much higher than PMNT single crystals.

Piezoelectric energy harvesting based on shear mode 0.71Pb(Mg 1/3 Nb 2/3 )O 3 -0.29PbTiO 3 single crystals

In this paper we theoretically and experimentally present a nonresonant vibration energy harvesting device based on the shear mode of 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 single crystals. The electrical properties of the energy harvesting device were evaluated using an analytical method. Good consistency was obtained between the analytical and experimental results. Under a mass load of 200 g, a peak voltage of 11.3 V and maximum power of 0.70 mW were obtained at 500 Hz when connecting a matching load resistance of 91 kΩ. A high output could always be obtained within a very wide frequency range. The results demonstrate the potential of the device in energy harvesting applied to low-power portable electronics and wireless sensors.

Fabrication of PIMNT/Epoxy 1-3 composites and ultrasonic transducer for nondestructive evaluation

In this paper, PIMNT/epoxy 1-3 composites with different volume fractions were prepared by the dice-and-fill method for application in ultrasonic transducers. The theoretical and experimental properties at different volume fractions and the temperature stability of the electromechanical property were investigated. The highest electromechanical coupling factor kt was obtained as 0.833 with the volume fraction of 0.58 and kt changed little below the Curie temperature of the single crystal. Afterward, an angle-beam transverse wave ultrasonic transducer using the fabricated composite was designed and manufactured based on the simulation of the KLM model and commercial software. The assembled prototype transducer showed large improvement in two-way insertion loss, relative bandwidth at -6 dB, surplus sensitivity, and axial resolution, which were -24.3 dB, 107%, 85 dB, and 28 dB, respectively, compared with a commercial PZT-based composite transducer.

High Curie temperature piezoelectric single crystals Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 and their applications in medical ultrasonic transducers

High Cure temperature and larger coercive field ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT or PIMNT) single crystals were grown, while maintain comparable piezoelectric properties with PMN-PT. We have designed and prototyped 1.6MHz ultrasonic transducers based on PIN-PMN-PT single crystals, which can be used in transcranial Doppler (TCD) ultrasonography. Compared with PZT-based TCD probe, the two-way insertion loss achieved by PIN-PMN-PT single crystals-based TCD probe is about 4 dB larger. The −6dB bandwidth of PIN-PMN-PT single crystal-based transducer is nearly 10% broader. The improvement of sensitivity and bandwidth of crystal-based probe reveal the great advantages in medical ultrasonic transducers applications. Besides, due to the enhanced beam-mode piezoelectric property of PIN-PMN-PT single crystals, the simulation results of ultrasonic phased array based on PIN-PMN-PT as well as PZT-5H ceramic reveal the significant improvements. The 4dB larger sensitivity, 40% shorter impulse response and 20% broader bandwidth (−6dB) of PIN-PMN-PT single crystal-based will certainly improve medical imaging quality. The PIN-PMN-PT crystals with large size, ultrahigh piezoelectric properties, good thermal stability, and attractive simulation results may become the promising candidate for medical ultrasonic transducers applications.