Regulation of Super Lattice Structure of Ferroelectrics by Homogeneous Precipitation Method with Polymer and Their Dielectric Property

The relaxor ferroelectrics have a broad peak on The temperature dependence of The dielectricconstant due to the diffuse phase transition at the curie temperature.这是difficult to preparethe single phase of perovskite structure for the类型relaxtors such asPb(Mg d21 / 3e D2Nb d22 / 3e D2)O - D23 D2(PMN), Pb(Ni d21 / 3e D2Nb d22 / 3e D2)O - D23 D2(PNN)，and Pb(Zn - d21 / 3e D2Nb - d22 / 3e D2)O - D23 - D2 (PZN). The temperature dependence of The dielectricconstant depends on the cation arrangement in the B site of the perovskite structure. in this study，the polyethylene glycol （PEG）可用来preparation of the relaxers. PEG can be coordinatedby the cations and can dissolve various kinds of metal salts. the PEG-cation complex was obtainedthe heat treatment of the PEG solution of the metal nitrate hydrate. the cation arrangement in thePEG-cation complex depended on the molecular weight of PEG. the PEG-cation complex consistedthe B site cations of the relaxers was oxidized. oxides which contains the A site cations weremixed with the oxides obtained by the oxidation of the PEG-cation complex so that PMN， PNN，and La. Doped PMN was obtained. The relation between The cation arragement in The PEG-cation complexand the amount of the obtained perovskite phase.When PMN was prepared by the oxidation ofpeg - cation complex)》,perovskite single phase was obtained at lower temperture than that the dry method was used. the格式amount of the super lattice structure in the La doped PMN increased with an increase of themolecular weight of PEG. The temperature dependence of The dielectric constant of PMN also dependedon the molecular weight of PEG. the single phase of the perovskite structure of PNN was obtained byadding 1 mol% BaTiO - D23 - D2 and the oxidation of PEG-cation complex。

The relaxor ferroelectrics have a broad peak on the temperature dependence of the dielectric constant due to the diffuse phase transition at the curie temperature. It is difficult to prepare the single phase of perovskite structure for the typical relaxtors such as Pb(MgィイD21/3ィエD2NbィイD22/3ィエD2)OィイD23ィエD2 (PMN), Pb(NiィイD21/3ィエD2NbィイD22/3ィエD2)OィイD23ィエD2(PNN), and Pb(ZnィイD21/3ィエD2NbィイD22/3ィエD2)OィイD23ィエD2 (PZN). The temperature dependence of the dielectric constant depends on the cation arrangement in the B site of the perovskite structure. In this study, the polyethylene glycol (PEG) was used for the preparation of the relaxers. PEG can be coordinated by the cations and can dissolve various kinds of metal salts. The PEG-cation complex was obtained the heat treatment of the PEG solution of the metal nitrate hydrate. The cation arrangement in the PEG-cation complex depended on the molecular weight of PEG. The PEG-cation complex consisted with the B site cations of the relaxers was oxidized. The oxides which contains the A site cations were mixed with the oxides obtained by the oxidation of the PEG-cation complex so that PMN, PNN, and La. Doped PMN was obtained. The relation between the cation arragement in the PEG-cation complex and the amount of the obtained perovskite phase.When PMN was prepared by the oxidation of PEG-cation complex, the perovskite single phase was obtained at lower temperture than that the dry method was used. The formed amount of the super lattice structure in the La doped PMN increased with an increase of the molecular weight of PEG. The temperature dependence of the dielectric constant of PMN also depended on the molecular weight of PEG. The single phase of the perovskite structure of PNN was obtained by adding 1 mol% BaTiOィイD23ィエD2 and the oxidation of PEG-cation complex.