The Research Of The Preparation And Properties Of P-type Semiconductor CaFe₂O₄ Doping With Transition Metal

With the continuous development of society, the field of the application of ferrite materials is more and more widely. Ferrite materials are mostly four directions of the structure of the n type semiconductor or insulator, But Ca Fe₂O₄ is rhombic crystal structure, and Ca2+ and Fe3+ can be easily replaced by other metal ions, this is leading to changing the electromagnetic transport properties of Ca Fe₂O₄.This paper using the sol- gel method prepared transition metal elements Zn and Cr doped p-type semiconductor Ca Fe₂O₄, studied the structure and magnetic transport properties of Ca1-x Znx Fe₂O₄ and Ca Crx Fe2-x O4, the main contents are as follows:Experiment using the sol- gel method with citric acid as the complex to the reaction of Ca1-x Znx Fe₂O₄ precursor was prepared, and then in 1000 ℃sintering 3 hours in the air, then we can get the powder. X-ray diffraction（XRD） results show that when x = 0.05, Zn Fe₂O₄ has appeared the second phase, this shows that Zn2+ in Ca Fe₂O₄ lattice doping concentration is very low.Experiment using the sol- gel method under the condition of different sintering temperature was prepared by different doping concentration Ca Crx Fe2-x O4 powder. X-ray diffraction results show that When annealing temperature reaches 1000 ℃ and sinters 2 hours, we can get pure Ca Crx Fe2-x O4 powder. At the same time, the X-ray diffraction（XRD） results show that when Cr doping concentration of 70%, the prepared Ca Crx Fe2-x O4 material by sol- gel method, still don’t have impurity peaks in the X-ray diffraction pattern. Fluorescence spectrum measurement result shows that Ca Fe₂O₄ powder prepared by sol-gel method with no doping appeared a glowing peak around 750 nm, which shows that the optical band gap is 1.65 e V.In addition, we also get Ca Fe₂O₄ lattice parameters according to the experiment and then use VASP software calculating the electronic structure of Ca Fe₂O₄.The first principles calculation results show that compared with non- magnetic and ferromagnetic Ca Fe₂O₄ characterized by antiferromagnetic always have the minimum and the most stable energy. The moment of Fe3+ in Ca Fe₂O₄ material is calculated at the time of antiferromagnetic alignment is 4.26 μB/Fe.