Effect of Zr 4+ on the properties of layered structured Ba(Ti 1− x Zr x ) 4 O 9 perovskites

Abstract

Solid solutions of Ba(Ti_1−xZr _x )₄O₉ (0 ≤ x ≤ 0.8) were fabricated via mixed oxides, solid state route. The phase, microstructural and dielectric properties of the fabricated samples were investigated. A structural phase transition was observed from orthorhombic (Amm2) to tetragonal (P4/mmm) with increasing Zr⁴⁺ contents (x ≥ 0.6). The dielectric constant (ϵ_r) increased with the substitution of Zr⁴⁺ contents which may be attributed to the larger ionic size and higher polarisability of Zr⁴⁺ relative to Ti⁴⁺. The maximum ϵ_r of 48.27 was observed for x = 0.2. The lowest dielectric loss (tan δ) of 5.5 × 10⁻⁴ and maximum quality factor (Q × f) of 5.6 × 10⁴ MHz were obtained (at 30 MHz) for Ba(Ti_0.8Zr_0.2)₄O₉ ceramics sintered at 1300°C for 2 h in air.