Bi_(1.5)Mg_(1.0)Nb_(1.5)O_7/Ba_(0.6)Si_(0.4)TiO_3 bilayer thin films prepared by pulsed laser deposition

摘要

Bi_(1.5)Mg_(1.0)Nb_(1.5)O_7/Ba_(0.6)Sr_(0.4)TiO_3 (BMN/BST) bilayer thin films have been prepared on Au/TiO_x/SiO_2/Si sub strates by pulsed laser deposition. The structure and electrical properties of BMN/BST bilayer thin films were investigated. X-ray diffraction results showed that the structure of BMN/BST bilayer thin films was composed of a cubic BMN pyrochlore phase and a cubic BST perovskite phase. The dielectric measurements showed that the BMN layer had played a positive role in improving the electrical properties of the thin Alms. With the increased thickness of BMN, the dielectric loss was significantly lowered, accompanied with a tolerable reduction of tunability. The BMN/BST bilayer thin films at a BMN/BST thickness ratio of 1 give the highest figure of merit of 61.5 and the largest commutation quality factor of 5163. In addition, the thickness effect was discussed with a series connection model of bilayered capacitors, and the calculated dielectric constant and loss tangent were obtained.