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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]

The relaxor-based ferroelectric single crystals Pb(In1/2Nb1/2)O3- Pb(Mg1/3Nb2/3)O3-PbTiO3 were grown successfully using the vertical Bridgman technique. The crystals were spontaneously nucleated and induced to grow by the seed respectively, with diameter of Ø25-40 mm and length of 80-170 mm. The [001]-oriented wafers of as-grown crystals showed the excellent electrical characterizations (ε∼5500, tanδ∼1.35%, d33 ∼1900pC/N, k33∼0.9). Both the higher rhombohedral-tetragonal phase transition temperature (Tr/t ∼100-120°C) and Curie temperature (Tc ∼170-200°C) enlarged the operating temperature range of the devices. The crystals had the stable time dependence of piezoelectric properties. Therefore, the successful growth and high performance made the crystal be a promising candidate for the ultrasonic applications. [ABSTRACT FROM AUTHOR]

Abstract: Relaxor ferroelectric-based Pb(Mg1/3Nb2/3)O3–32PbTiO3 (PMN–32PT) single crystal growth and thermal analysis were reported. The as-grown PMN–32PT crystal was determined by XRD to be a single phase with rhombohedral structure at room temperature. The Curie temperature was in the range of 137–146°C with ferroelectric rhombohedral to tetrahedral phase transition temperature of 92–118°C. The piezoelectric coefficients were about 2000pC/N with longitude electromechanical coupling factors about 0.93. DSC/TGA analysis of the as-grown PMN–32PT crystal indicated that the melting point of PMN–32PT was 1302.1°C in sealed condition while reduced to 1282.9°C in open system due to the evaporation of PbO and the transformation into pyrochlore phases. [Copyright &y& Elsevier]

A Pb(In 1/2 Nb 1/2)O 3 –Pb(Mg 1/3 Nb 2/3)O 3 –PbTiO 3 relaxor ferroelectric single crystal with a 5" diameter and 145 mm length was grown by the modified Bridgman method. The composition distribution of the crystal boule was investigated. The result showed that the PbTiO 3 contents increased along the growth direction, which means that compositional segregation existed, and the effective segregation coefficient was simulated to be 0.84, which is close to that of 3" single crystal. The horizontal composition distribution in the crystal demonstrated that the solid-melt interface of the 5" single crystal was serious convex during crystal growth and was caused by the nonuniform radial thermal field of the large melt. The dielectric, piezoelectric, ferroelectric properties and domain structures were measured to investigate the effect of the composition change along the crystal growth direction. Based on the domain structure and electrical performance, the crystal boule was divided into rhombohedral, morphotropic phase boundary and tetragonal regions. It was found that the optimal piezoelectric coefficient d 33 of the 5" single crystal was more than 2000 pC/N. This work provided positive information for large sized single crystal growth of a relaxor ferroelectric single crystal. • The 5'' diameter by 145 mm long of PIN-PMN-PT crystal along [110] direction was grown by the modified Bridgeman method. • The compositions of single crystal samples along the crystal growth direction and horizontal direction were measured for compositional segregation and horizontal component distribution effect of 5 inches single crystal growth. • The dielectric, piezoelectric and ferroelectric properties of [001] C samples along the crystal growth direction were investigated. Considering the performance of all samples, the crystal in the rhombohedral phase near MPB are suitable for engineering applications. [ABSTRACT FROM AUTHOR]