Enhanced dielectric tunability of Ba_xSr_(1-x)TiO_3-MgO composite ceramics co-modified with CuO and MnO_2

摘要

0.55Ba_xSr_(1-x)TiO_3-0.45MgO composite ceramics (BST-MgO, x = 0.5-0.65) co-modified with CuO and MnO_2 were prepared by conventional soild state reaction method. The microstructure, phase and morphology were investigated. The results showed the formation of the perovskite BST phase and MgO phase. The dielectric constant (ε_r) and tunability (T) of the ceramic samples increased with increasing Ba content. The dielectric loss (tan δ) and figure of merit achieved their minimum and maximum at x = 0.6, respectively. The obtained ceramic sample with x = 0.6 exhibited favorable properties, which are listed as follows: ε_r = 190, tan δ = 0.22 %, T = 16 %, E_c = 5.6 kV/cm and FOM = 72.7.