THE INSERTION EFFECT OF Bi-EXCESS LAYERS ON STOICHIOMETRIC BiFeO₃ THIN FILMS PREPARED BY CHEMICAL SOLUTION DEPOSITION

The insertion effect of Bi -excess layers on stoichiometric BiFeO ₃ thin films prepared by chemical solution deposition is investigated. A stoichiometric BiFeO ₃ thin film with both the Bi -excess top and bottom surface layers shows improved crystallinity with the remanent polarization of 65 μC/cm² at 80 K, which is larger than for BiFeO ₃ film prepared by the same process using stoichiometric solution. These results are attributed to the reduction of the imperfect crystal at the interface between the BiFeO ₃ film and electrode. By inserting Bi-excess layers, the saturated magnetization of all the films becomes smaller than that of the film using stoichiometric solution. Bi -excess surface layers at the top and bottom interfaces are an effective way to obtain good ferroelectric properties.