Investigation of dielectric and flexoelectric properties of chemically gradient BaxSr(1-x)TiO3 ceramics

Abstract

The rapid evolution of electronic devices has increased the emphasis on optimizing the electromechanical responses of lead-free ceramic materials. Recently, flexoelectricity in ceramic materials has garnered significant interest due to its potential applications. Doping is a key strategy for optimizing the dielectric properties of materials, but research on the tailoring of strain gradients across materials should not be neglected. To address this, we prepared cast films of Ba_0.7Sr_0.3TiO₃, Ba_0.8Sr_0.2TiO₃, and Ba_0.9Sr_0.1TiO₃ by adjusting the ratio of barium to strontium. These films were stacked in the thickness direction and sintered to create a compositional gradient, to obtain ceramic sheets with enhanced properties. The gradient ceramic sheets exhibited a low dielectric temperature coefficient, demonstrating excellent temperature stability, alongside a pre-existing strain gradient that enhanced the ceramic flexoelectric coefficient to 54.48 μC·m⁻¹. Compared to single-component barium strontium titanate ceramics, this improvement makes gradient ceramics more advantageous for electronic device applications.