Microstructures and electrical properties of Ba_0.9Sr _0.1Ti_0.99Mn_0.01O₃ multilayers

Two Ba_0.9Sr_0.1Ti_0.99Mn _0.01O₃ (BSTM) multilayers have been prepared by using a chemical solution deposition method based on precursors with (sample A) and without polyvinylpyrrolidone (PVP) additive (sample B). Microstructures were characterized by X-ray diffraction and transmission electron microscopy (TEM). Detailed electrical properties including dielectric constant, loss tangent, tunability at low frequency and leakage current were measured. Compared with sample B, sample A had improved dielectric properties, with higher tunability of 48% (at 340 kV/cm), lower dielectric loss of ∼0.05 and less frequency dispersive. The leakage current of sample A was lower than that of sample B at low electric fields (<400 kV/cm) and was higher than that of sample B when the electric field was above 400 kV/cm. The leakage currents are governed by Ohmic conductivity at low applied electric fields for both samples. At high electric fields, sample A showed a Poole-Frenkel dominated leakage behavior while sample B seemed to be controlled by a combination of Schottky and Poole-Frenkel emissions.