Formation of nano-Ag/BiFeO3 composite thin film with extraordinary high dielectric and effective ferromagnetic properties

The Ag/BiFeO3 composite thin films were prepared by sol-gel technology on ITO/glass substrate. Most of the Ag+ ions were reduced to form Ag nanoparticles in the thin film. Some Ag+ ions were doped into the BiFeO3 lattice to replace Bi, forming Ag doped BiFeO3. The average size of the Ag nanoparticles is 4-8 nm. The dielectric constant of the BiFeO3 thin film sintered at 550 A degrees C with the molar ratio of Ag/Fe of 0.2 was enhanced to 139, which was nearly twice as high as that of pure BiFeO3. The dielectric loss kept at a low value of 0.15. The composite thin film also showed a typical ferromagnetism with the saturation magnetization of 2.2 emu/cm(3). The Ag/BiFeO3 composite thin film showed typical ferromagnetism and high permittivity simultaneously.