A study on the electrical properties of flux grown 0.91PZN-0.09PT single crystals for high-performance piezoelectric and pyroelectric device applications

Abstract

In the present work, large-size piezoelectric single crystals of 0.91[Pb(Zn1/3Nb2/3)O3]-0.09PbTiO3 (PZN-9PT) have been grown by high-temperature flux method. Rietveld refinement analysis of X-ray diffraction data demonstrates the existence of monoclinic [Cm and Pm] phases, further supported by electron diffraction studies. PZN-9PT single crystal shows broad and diffused dielectric response peaks at 354 K and 443 K with noticeable frequency dispersion identified from temperature-dependent dielectric measurements. The 001 oriented PZN-9PT elements sliced from the grown single crystals display a remnant polarisation (Pr) of 30 µC/cm2, saturation polarization (Ps) of 33 µC/cm2, and an enhanced piezoelectric strain of 0.3 %. In addition, the piezoelectric coefficients d33, d31 and electric field-induced strain d33∗ measured by the direct method is 2100 pC/N, 1650 pC/N and 2500 pm/V, respectively. The mechanism behind the enhanced piezoelectric properties of PZN-9PT is explained with reference to the stabilization of the monoclinic phase and polarization rotation mechanisms. Further, the pyroelectric coefficient, p measured to be 11.31 × 10−4 C/m2 K at room temperature and 51.22 × 10−4 C/m2 K at the ferroelectric to the paraelectric phase transition temperature. The enhanced piezoelectric and pyroelectric properties of PZN-9PT make them suitable for high-performance piezoelectric transducers, actuators at ambient temperature and pyroelectric sensors at elevated temperature, respectively.