关键词: 铁电膜, 自旋, BethePeierls近似, 平均场近似, 磁化强度, 转变温度

Abstract: The magnetization of spin-1/2 ferroelectric thin films consisting of 6 and 20 atomic layers is calculated by using Bethe-Peierls approximation within a layer and mean field approximation between layers. It is found that the surface magnetization is different obviously from the average magnetization of the films if the surface bonding strength is not the same. The surface magnetization is weaker than the entire one if the surface bonding strength is low, and vice versa. However, both the surface and entire magnetization have the same transition temperature. So, for a thicker film, the entire magnetization of film is affected slightly by the surface bonding strength, while the strong surface bonding strength will bring a thin film to be magnetized entirely in the vicinity of transition temperature. The transverse field will restrain the spontaneous magnetization of the film.