Fabrication And Characterization Of The Tantalum Oxide Films

With the progress of science and technology,nanomaterials have gradually entered the field of vision.In order to improve the performance of products,factors affecting the properties of materials have been studied in depth.Tantalum oxide,as a wide band gap metal oxide,has good photoelectric properties and is the first choice in this paper.After investigation,it is found that most of the research on tantalum oxide is concentrated in the field of electricity,and the study of magnetic properties is very few.The reasons for the ferromagnetic appearance of Ta₂O₅ films at room temperature are also different.In order to explain this problem reasonably,the tantalum oxide was prepared by magnetron sputtering.The morphology and magnetic mechanism of the tantalum oxide were studied by XRD,FE-SEM,EDS,MPMS and PPMS.The concrete results are as follows:?1?Ordered porous aluminum oxide?AAO?was prepared by two anodization.Then ordered porous Ta₂O₅ thin films were prepared by magnetron sputtering on alumina substrate.Due to the different conditions,the prepared samples are different,so this paper studies the effects of different oxygen flow,different base temperature and different sputtering time of samples.The results show that the temperature of the substrate has no significant effect on the preparation of the samples.The morphology of the samples was characterized by SEM.It was found that with the increase of sputtering time,the diameter of the Ta₂O₅ film decreased and the thickness increased.The optimum conditions for the preparation of pure ordered porous Ta₂O₅ films were obtained.?2?The relationship between the magnetic properties of the samples and the preparation conditions was studied.By MPMS and PPMS,it was found that the Ta₂O₅ films were ferromagnetic at room temperature.With the increase of oxygen flow,the magnetic properties of the samples increase first and then decrease.The magnetic properties of samples perpendicular to the surface of the membrane are much larger than those of the samples parallel to the magnetic field of the film surface.This result indicates that the Ta₂O₅ thin films have magnetic anisotropy.At the same time,the saturation magnetization of the sample decreases with the increase of sputtering time.?3?The relationship between the magnetic properties of the samples and the annealing environment was studied.To study the effect of oxygen vacancies on the magnetic properties of the samples.The samples were annealed and the PL spectra were tested.The effects of different annealing environment and different annealing time on the samples were tested.Annealed in air and vacuum,and compared with untreated samples,the results showed that the magnetic properties of samples increased after vacuum annealing,and the magnetic properties of samples decreased after annealing.This result accords with the PL spectrum,indicating that the magnetic properties of the Ta₂O₅ film are related to the oxygen vacancy.In order to reconfirm this conclusion,the samples are annealed at different times in the air.The results show that the magnetic properties of the sample gradually weaken with the increase of annealing time,which is in accordance with the former.The relationship between magnetic properties and temperature of the samples is tested and fitted.It is concluded that the ferromagnetism of Ta₂O₅ films is consistent with the spin wave theory.The origin of its magnetism is similar to that of iron,cobalt and nickel.At the end of this paper,the ferromagnetic mechanism of Ta₂O₅ film is explained.Its magnetic properties are not only related to the special porous structure of the material,but also closely related to the oxygen vacancy of an electron.In the experiment,the quantitative control of the magnetic properties of Ta₂O₅ film can be achieved by controlling the number of oxygen vacancies to prepare the qualified samples.