Preparations And Room Temperature Ferromagnetism Of Fe And Ni Co-Doped In₂O₃ Dilute Magnetic Semiconductor

Nowadays,Spintronics attracts more and more attentions,the development significantly enriches the condensed matter physics.If we can make full use of both the charge carrier and the vector spin bitangent information characteristics of electronic properties to design new electronic information devices,it will greatly enhanced the ability of information processing and develop a new mode of information processing and storage.Diluted magnetic semiconductor which may have the spin degree of freedom is considered most likely to become the spin electronics materials.In₂O₃ can be an n-type semiconductor with high conductivity by introducing oxygen deficiencies or by transition metal-doping,which has good ferromagnetic at room temperature,conductive,transparent,gas-sensing.The study of In2O3-based diluted magnetic semiconductors become a hot research field.In this research,(In_0.9-xFe_0.1Ni_x)₂O₃(0≤x≤0.03) bulks and thin films were prepared by high-temperature solid-state reaction and Electron Beam Evaporation evaporation method.The crystal structure,magnetic property were investigated by X-ray Diffraction(XRD),Scanning Electron Microscope(SEM),Vibrating Sample Magnetometer(VSM).We had studied on how the different concentration of Ni doping on the Fe:In₂O₃ system and the preparation of bulk and film samples of process parameters affect to the structure and magnetic properties of the samples. Then,we get a good process parameters.First,(In_0.9-xFe_0.1Ni_x)₂O₃(0≤x≤0.03) bulks were prepared by high-temperature solid-state reaction.From comparing the SEM pictures of three samples with different sintering temperatures,we find when the sample with 1100℃sintering had a best crystal structure.Secondly,we analyses the XRD and VSM pictures of the bulk samples.When x≤0.02,samples were single-phase and had the structure similar with In₂O₃ cubic crystals.When x≥0.02,impurity phase NiFe₂O₄ was appeared.The main phase of the lattice constants first reduced then increased as increasing the value of x,the minimum reach to 1.005 nm when x = 0.02.The samples without Ni were paramagnetic.The samples with Ni-doped were ferromagnetic at room temperature, and the Saturation magnetization were increasing with the increasing contents of Ni. The doping of Ni not only had bring Additional Carrier concentration,but also enhanced the total magnetic moments of the system.This indicates that the source of magnetic is closely related to doping and defects caused by the system of concentration.The spin electrons need carriers as media to couple each other.Finally,optimum study of technological parameters for the preparation of x = 0.02 film samples by Electron Beam Evaporation method was carried through orthogonal design.The optimum technological parameters for the best physical properties of thin films were that the substrate temperature was 400℃,the oxygen argon flow ratio was 10/0.