The effect of Li2CO3 sintering additive on the dielectric and tunable performance of (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3-CuO ceramics

Abstract (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3-2 mol% CuO + x mol% Li2CO3 ceramics are obtained at low sintering temperature (1100 °C) by solid-state reaction method to study the effect of Li2CO3 sintering additive on the structure, dielectric and tunable performance of (Ba0.91Ca0.09)(Zr0.2Ti0.8)O3-CuO ceramics. The XRD results suggest that Li+ occupies A site firstly (for x = 1 and 2) and then occupies B site (for x = 3 and 4). It brings to the variation of lattice structure, which results in the non-monotonic shift of Tm. The SEM shows that appropriate Li2CO3 sintering additive can promote the grain growth. The maximum average grain size obtained at x = 2 makes it possess a higher permittivity (8336) at room temperature and a larger tunability (48.03%) at a low bias electric field value of 7 kV/cm. Accompanied with its low tan δ (0.00286), a high FOM value of 167.95 is achieved. These results suggest that the prepared ceramics are more attractive to be used as tunable devices due to its low sintering temperature and high FOM at a low bias electric field.