Synthesis And Properties Of Iron Oxide Nanoporous Films

With the development of science and technology,energy conservation and miniaturization of devices have attracted more and more attention.Therefore,how to realize the multifunctionality of materials and simultaneously utilize the different functions of these materials in devices will be an important development direction in the field of multifunctional materials.This paper selects the ordered porous iron oxide film as the research object,and studies its preparation method,structure color,magnetic properties and resistive switching?RS?characteristics.It is hoped that it can help to develop multifunctional high-density memory media materials.?1?We produced the porous iron oxide film on a pure iron foil by electrochemical anodization.It was anodized in ethylene glycol?EG?solution consisting of 0.1 M ammonium fluoride?NH₄F?and 1 M H₂O.It is found that the morphology of the pores is disordered,and the structure of the films could be adjusted with different anodization time and temperature.?2?It was found that the porous iron oxide with tunable structural colors in the entire visible range prepared by electrochemical anodization.The relationship between the structural color and the anodization time and the electrolyte temperature was discussed.The results showed that the maxima of the reflected wavelengths in the UV-Vis reflectance spectra were consistent with the observed colors.?3?We provided an effective method to determine the carrier type according to the free electron gas model.It was found that the n² was about equal to the effective dielectric constant?of the films,and it proves that the porous iron oxide film is an n-type semiconductor.?4?Ordered porous iron oxide thin film was successfully prepared on porous anodic alumina?PAA?substrates using DC-reactive magnetron sputtering.It was found that the arrangement of the film was consistent with the PAA substrates,showing a hexagonal structure.The pore diameter gradually decreases and the thickness of the film increases with the increase of sputtering time.Finally,a dense film is formed.The results of X-Ray Diffraction?XRD?measurement show that the sample is amorphous.?5?The room-temperature magnetic properties of ordered porous iron oxide/PAA composite films were characterized.It was found that the composite film has obvious room-temperature ferromagnetism,and the sample has obvious magnetic anisotropy.The direction perpendicular to the film surface is the direction of easy magnetization.On this basis,Ag/iron oxide/PAA/Al devices were further prepared.The I-V test results showed that the devices prepared had bipolar resistance switching characteristics.By triggering the device to a high-resistance state?HRS?or a low-resistance state?LRS?,it is found that the magnetic properties of the device under different resistance states are significantly different,which indicates that the magnetic properties of the film can be regulated by an electric field.This kind of magnetization can be controlled by electric field at room temperature,and it is expected to be used in spin electronics and multifunctional data storage.