The effect of MnO2-doping on the microstructure and microwave dielectric properties of BST/MgO composites

Abstract MnO 2 -doped barium strontium titanate–MgO (BST/MgO) composites were sintered by the solid-state reaction method. The effect of MnO 2 -doping on the microstructure and microwave dielectric properties of the BST/MgO composites was investigated. The MgO grains were found to be surrounded by Mn-rich oxides, which hindered the incorporation of Mg 2+ into the lattice of BST. As a result, enhanced comprehensive microwave dielectric performances, such as the reduction of dielectric loss and leakage current about 0.78 nA/cm 2 , and an increase of electric field tunability of dielectric constant about 13.8% at 5 kV/mm were obtained in MnO 2 -doped BST/MgO ceramics.