Study On Preparation And Electromagnetic Properties Of Transition Metal Oxide Sr₂IrO₄ And Doped

In this paper,first,we mainly study the transition metal oxide Sr₂IrO₄,whose structure not only has high similarity to K2NiF4（La₂CuO₄）,but also has many interesting phenomena in terms of the electrical and magnetic properties.Here,the samples are prepared by a conventional solid-phase synthesis method.And the poly-crystalline samples are characterized and their electromagnetic properties are measured by X-ray diffraction,physical property measurement system,magnetic property measurement system and scanning electron microscope.According to the experimental data,we can get the resistance of this material increasing with the temperature decreasing.Especially,when the temperature is at 50 K,the resistance rises to infinity rapidly.This shows that Sr2 Ir O4 which should be metallic is an insulator with weak ferromagnetism,that is,the Mott insulator.The material Sr₂IrO₄ has an obvious magnetic transition phenomenon around 240 K.But around 150 K,there is a bifurcation between the zero-field cold and field-cold branches of the magnetization data.It is interesting that MZFC decreases to the lowest measuring temperature sharply below 95 K,while MFC monotonically increases with a small slope.This phenomenon may be related to its inherent nature.After that,we have a detailed exploration for Ti-doped Sr₂IrO₄ that is the transition metal oxide with 5d electron configuration,and study physical properties and preparation of the sample whose doping concentration is ten percent.The data show that the resistance behavior of the poly-crystalline material Sr2Ir0.9Ti0.1O4 is consistent with that of the insulator.For this material,although its magnetic transition temperature at about 240 K is unchanged,the magnetization becomes smaller.In addition,we analyze Sr_1.95La_0.05IrO₄ and Sr_1.95Ca_0.05IrO₄.Here,the resistance of La-doped sample becomes smaller and the magnetic transition is suppressed.But for Ca-doped sample,they both become larger,which is related to its own ionic radius and then has an effect on the oxygen hexahedral structure.We suppose that with the increasing of La doping concentration,the material may present superconductivity;and with the increasing of Ca doping concentration,the insulation of the material becomes stronger.Second,we study the perovskite structure of the transition metal oxide SrTiO_3-δ.It is found to be metallic,which is related to its oxygen vacancy.In conclusion,this article provides an important reference value for studying theproperties of transition metal oxide Sr₂IrO₄ and SrTiO_3-δ,which can deepen our understanding of this system.