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The low uniformity in properties of relaxor ferroelectric crystals is a long‐standing issue in the ferroelectric community, which limits the available volume of the entire crystal boule. The aim of this study is to develop a relaxor ferroelectric crystal with improved property uniformity and excellent piezoelectricity. To this end, Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 is doped with Nd2O3 (Nd–PIN–PMN–PT) to improve the crystal performance. Along the crystal boule, the piezoelectric coefficient d33 varies from 2800 to 3500 pC N−1, and the dielectric constant ranges from 8400 to 9800, with variations of 25% and 16%, respectively. Such high property uniformity results in over 75% available volume of the crystal boule, compared to 30–50% for undoped crystals grown by Bridgman method. At the electric field of 1 kV cm−1, the converse piezoelectric response is up to 4780 pm V−1. In addition, its Curie temperature (TC) and coercive field (EC) are above 150 °C and 3 kV cm−1, respectively. Compared with Pb(Mg1/3Nb2/3)O3–PbTiO3 crystal (d33: 1500 pC N−1, TC: 135 °C, EC: 2.3 kV cm−1), the larger piezoelectricity, the higher TC and EC, and improved uniformity make Nd–PIN–PMN–PT crystals promising candidates for advanced piezoelectric applications. [ABSTRACT FROM AUTHOR]

Relaxor‐PbTiO3 crystals exhibit excellent piezoelectric properties (d33 > 2000 pC N−1 and k33 > 90%) and thus attractes widespread attention in the past two decades. However, the inevitable segregation of components during the crystal growth results in relatively low‐performance consistency of Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT) crystals, which seriously affects their practical applications. In this work, Nd3+ as A‐site substitution is introduced to improve the uniformity of electromechanical performance of PMN‐PT crystal. The results show that the crystal exhibits a high piezoelectric coefficient of 3000 pC N−1 in rhombohedral phase with a variation of 36%. The electron probe X‐ray microanalyzer indicates that the opposite separation characteristics of Nd3+ and Ti4+ lead to improved uniformity of piezoelectric performance along the crystal boule. The giant piezoelectricity in Nd‐doped PMN‐PT is attributed to the enhanced local structural heterogeneity introduced by doping Nd. Furthermore, the Nd‐doped PMN‐PT crystal shows the rhombohedral‐tetragonal phase transition temperature in the range of 74–87 °C, which indicates that Nd‐doped PMN‐PT crystal can be a promising candidate for the design of advanced piezoelectric transducers. [ABSTRACT FROM AUTHOR]

Relaxor-PbTiO3 (PT-based) ferroelectric single crystals are important for many piezoelectric applications because of their outstanding performances. In order to expand their usage and avoid the failure during application, frequency dependence of coercive fields EC for [001]- and [011]-poled rhombohedral Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals was investigated from the frequency of 1 Hz to 300 kHz by using hysteresis loop measurement (frequency: from 1 Hz to 2 kHz) and a critical value method (frequency: from 5 to 300 kHz). The results showed that the coercive field EC, remnant polarization Pr, and saturation polarization Ps strongly depended on the crystal orientation and frequency. Compared with the [001]-poled crystals, the [011]-poled PIN-PMN-PT single crystals possessed higher EC, Pr, and Ps at the same testing frequencies. With increasing frequency from 1 Hz to 300 kHz, the coercive fields EC of the [001]- and [011]-poled PIN-PMN-PT single crystals increased from 4.0 and 4.8 kV/cm to 11.5 and 14.9 kV/cm, respectively. Moreover, the frequency dependence of the coercive fields was found to be consistent with the growth kinetics model, where the coercive fieldsEC were proportional to ƒβ. This work benefits to the design of piezoelectric devices based on PIN-PMN-PT single crystals operated at high frequencies and high driving fields. [ABSTRACT FROM AUTHOR]

Relaxor based ferroelectric single crystals Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PIN-PMN-PT) with composition near morphotropic phase boundary exhibit extraordinary piezoelectric properties. Due to the composition segregation during crystal growth, the composition and properties of PIN-PMN-PT single crystal boules are poor uniformity. In this work, uniformity of dielectric and piezoelectric properties of the crystal boules with 4″ diameter by 100 mm long were clearly improved along the crystal growth direction by the modified Bridgman method. For 70% length of the boule, T RT and Tc were around 100 °C and 160–180 °C along the growth direction, respectively. The variety of piezoelectric constant d 33 is about 1500-1800pC/N in the same range of the boule. So that PIN-PMN-PT crystals will be more cost-effective and beneficial for ultrasonic applications in higher temperature region. [ABSTRACT FROM AUTHOR]