Study On Magnetic And Electrical Properties Of Thin Film Structure SrCoO_3-? System

In recent years,there has been a boom in the research of perovskite materials.Perovskite materials have become the focus of solar cells,fuel cells,catalysts,sensors,luminescent materials,magnetic recording and other fields.The need to make devices smaller and more versatile has led many people to investigate the properties of thin films made from materials.SrCoO_3-?(SCO_3-?)perovskite has different crystal structures and physical properties with the change of oxygen content.Although many properties of the film have been widely studied,its magnetic and electrical properties have not been fully studied.This paper was focused on the magnetic and electrical properties of the material system SrCoO_3-?.The main works were summarized as follows:?Solid phase SrCoO_3-?films were prepared by solid phase reaction and pulse laser deposition?PLD?.As the temperature increases,the magnetic property of the film becomes weaker,and the maximum saturation magnetization at 2K is 30emu/cm³.The metallic-insulator transition?MIT?process occurs in SrCoO_3-?film from 10K to 300K,and the process is reversible.We used the Mott's law to fit the curves,and the results showed that the electrical transport mechanism in the high temperature zone?T>Tm?is variable-range hopping?VRH?.From the test results of magnetic and electrical properties of the material,it can be seen that it has a great prospect in the practical application of sensors and memory materials.?The SrCo_1-xFe_xO_3-??x=0,0.2,0.6?thin films were prepared by solid phase reaction and PLD.We also observed the MIT in the SrCo_1-xFe_xO_3-?film from 2K to 400K.The reduced film thickness and doping induced the increase of the transition temperature.We used the Mott's law to fit the curves,and the results showed that the electrical transport mechanism in the high temperature zone?T>Tm?was still VRH.?SrCo_1-xFe_xO_3-??x=0,0.2,0.6?films were prepared by solid phase reaction and PLD.In contrast,oxygen pressure was not provided during the preparation of SrCo_1-xFe_xO_3-?films.Therefore oxygen vacancy increased.The film thickened as oxygen vacancies increased.The MIT occurred in SrCo_1-xFe_xO_3-?films from 2K to 400K and the transition temperature increased again when the doping level was0.2.We used the Mott's law to fit the curves,and the results showed that the electrical transport mechanism in the high temperature zone?T>Tm?was still VRH.The doped 0 or 0.6 showed the electrical properties of the insulator,which indicated that the lower doping content can cause the MIT phenomenon in the case of more oxygen vacancies.