The Modulation Of Physical Property In Layered Functional Oxides Sr₁₄Cu₂₄O₄₁,Sr₂IrO₄,Bi₆Ti₃Fe₂O₁₈

The electric,optical,magnetic,and thermalproperties of functional oxides have been attracted considerable attentions,because of their fundamental interests and potential applications.These basic properties are closely related to the chemical composition,microstructure,and preparation.Therefore,in order to get superior functionalities,it is necessary to understand the basic properties of functional oxides.In this thesis,three kinds of layered functional oxides Sr₁₄Cu₂₄O₄₁,Sr₂IrO₄,and Bi₆Ti₃Fe₂O₁₈ have been investigated,and the physical properties of each systems and their deviates have been carefully characterized through various techniques.The first part:the sample was prepared by solid state reaction method.The lattice constants are determined by X ray diffraction measurements.The measurement of XPS provides the electronic structure information of Sr₁₄(Cu_1-xRu_x)₂₄O₄₁:study of the Cu ions average valence for undoped and doped samples show that the Cu ions are mainly+2 valence,and only a very small part are Cu³⁺ion;XPS spectrum of O1s in three samples show that a small shoulder of an undoped sample in the direction of low binding energy is considered to be a plasma excited by a hole carrier,but the sample after doped is formed by the Ru-O bond.Further analysis of Sr3d and Ru3d indicate that they are+2 and+4 valence states,respectively.The test and analysis of the electrical transport properties show that the increasing resistivity of the sample with the increase of the doping concentration,and the electrical conductivity increases first and then decreases.It is revealed that the hole carrier concentration on the Cu₂O₃ spin ladder decreases first and then increases.Further analysis shows that there is a crossing temperature of T_?²06K on the relation curve of resistance and temperature.There are two kinds of conduction mechanism in the system:the thermal excitation of a single hole on the spin ladder is contributed to the conductivity above T_?;below T_?,the localized cavitation jump conductance of one dimension pair is the main function.In addition,this paper also measure the magnetic susceptibility at 1T magnetic field and10-200K temperature range.The fitting parameter analysis shows that the Ru doping enhanced the two dimensional properties of the system and increased antiferromagnetic interaction,and the coupling of the magnetic and electronic states is further discussed by the fitting parameters.The second part is to prepare series?Sr1-xLax?2IrO4 single crystal samples by flux method.XRD diffraction analysis showed that all the single crystal samples were single phase.Through a series of fitting and theoretical analysis of the resistivity temperature curve,it has revealed the conduction mechanism of(Sr_1-xLa_x)₂IrO₄ single crystal sample in each temperature zone,and obtained the various parameters of the corresponding conductive mechanism through a series of theoretical calculations.The third part:single phase Bi₅SmTi₃Fe₂O₁₈ ceramic samples were prepared by sol-gel method.X ray diffraction results showed that the prepared samples were single phase.The measurement of relative permittivity shows that typical dielectric relaxation are observed,and the relative dielectric loss is very small.The complex impedance and ac conductivity were further measured,and the corresponding thermal activation energy was obtained,to further analysis the polarization process.