Effect of Mn doping on the structural and electrical properties of periodic Ba0.9Sr0.1TiO3 multilayers

Undoped and Mn-doped periodic BST multilayers have been prepared by chemical solution deposition method. Mn2+ tends to substitute for Ti4+ in the BST lattice and introduces more oxygen vacancies, which leads to the reduction of the concentration of electrons and the downward shift of the Fermi level. As a result, improved electrical properties, such as lower frequency dispersion of the dielectric constant, lower dielectric loss and leakage current were found for Mn-doped samples. However, excessive Mn leads to the coexistence of Mn2+ and Mn3+ (or Mn4+), which is believed to degenerate the electrical performance of BST multilayers. 1 mol% Mn-doped BST multilayer exhibits the best electrical performance, with leakage current density of 2.1 × 10−5 A/cm2 (at 100 kV/cm), dielectric loss of ∼0.08 (at 10 kHz) and the minimum frequency dispersion of the dielectric constant.