Thermal expansion studies in lead iron niobate — Lead zinc niobate and related systems

Dielectric and thermal expansion studies have been carried out in the relaxor ferroelectric system of PFN1 − X-PZNX. These compositions show two distinct regions of thermal expansion behaviour from room temperature to 800 K. As the Tc of the system increases, the lower expansion region extends. At higher values of x (> 0.7), the pyrochlore phase appears, resulting in higher values of α. Addition of BaTiO3 suppresses the pyrochlore phase and reduces the magnitude of a in the relaxor region. The width of the low expansion region is also reduced due to the lowering of Tc in these compositions.