Dielectric and mechanical nonlinearities of ⟨001⟩ oriented pure and doped single crystals of PZN-4.5PT

Abstract

This paper presents an overview of nonlinear dielectric, electromechanical, piezoelectric relationships in pure and Mn doped single crystals PZN-4.5PT and some modelling. The study of Mn doping on ⟨001⟩ oriented PZN-4.5PT single crystals confirms that pure crystals have soft material behaviour, while doped ones have hard material behaviour. This change in structure of the material has an effect on the dielectric, piezoelectric and mechanical properties by decreasing the dielectric constant (5650 to 3500), the dielectric losses (0.39 to 0.33) and the piezoelectric coefficient (−1050 to −650) and increasing the mechanical quality factor (150 to 375) and the velocity (1150 to 1410). It is found that the pure crystals show behaviour, under strong field or stress, that follows the Rayleigh law while the doped crystals show quadratic behaviour. Research has been undertaken to understand the influence of Mn doping on the stability in temperature for the dielectric constant, and d31 and the ageing effect. It appears that Mn neatly stabilizes the crystals compared to the pure ones.