THE INSERTION EFFECT OF Bi -EXCESS LAYERS ON STOICHIOMETRIC BiFeO 3 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.