| As a kind of ABO3 structure’s composite oxide, La Sr Fe O3 is an electronic functional material which applied in various fields, such as high temperature solid oxide fuel cell, thin film sensor catalyst, and ferroelectric materials. In this paper, according to the chemical dosage ratio, prepared 20 ml precursor sol by sol-gel method with acetic acid lanthanum, strontium acetate, ferric nitrate, nickel acetate, magnesium acetate, chromium nitrate, cobalt acetate, manganese acetate as raw materials, and ethanolamine acetylacetone as complexing agent. Rotation the wet film on the Si/Si O2 /Pt substrate after aging a day. Getting the LSF-M(M=Mg, Ni, Cr, Co, Mn) thin film samples with recondition 300 s and 400℃, and annealing at different atmospheres(air, oxygen, argon annealed at 750℃). Study on the influence of element substitution and annealing atmosphere on the electrical properties of La0.5Sr0.5Fe O3 thin film structure and dielectric.It was found out that the dielectric properties can be improved by dopd the La0.5Sr0.5Fe O3 films with Mg, Ni, Cr, Co, Mn element respectively. And then we studied annealing atmosphere(air, oxygen, argon) effect on the structure and dielectric electrical properties of LSF thin film on this basis, it was found that the films annealing at atmosphere of argon, dielectric properties can be optimized. And analysis of XRD and SEM indicate that the perovskite structure of LSF thin films did not changed with element substitution and annealing atmosphere. And thin film in each of the optimal performance of the flat surface, homogeneous with no obvious hole defects such as cracks.The Mg element could improve the film’s ?r, but with the increaseing of Mg content, the ?r of La0.5Sr0.5Fe1-x Mgx O3 thin films decreased gradually, the tanδ increased gradually.And the optimal amount of Mg is 5mol%, dielectric properties of thin film optimal. Dielectric properties of La0.5Sr0.5Fe0.95Mg0.05O3 thin films are different when annealing at different atmosphere(air, oxygen, argon). La0.5Sr0.5Fe0.95Mg0.05O3 thin films at argon can be obtained optimal dielectric properties, the ?r and tanδ was 1632, 0.041; annealing with the air is second, the ?r is 1409, and tanδ is0.047; annealing with oxygen was relatively low, the relative ?r is 1256, the tanδ is 0.115.The dielectric properties of LSF thin films can be improved by doping with Ni, along with the increase of the content of Ni(0.2, 0.25, 0.3mol%), the ?r of La0.5Sr0.5Fe1-x Nix O3 thin films firstly increased and then decreased, but increased the ?r even, tanδ was decreased and then increased. The optimal amount of Ni was 0.25mol%(La0.5Sr0.5Fe0.9975Ni0.0025O3 thin films) the dielectric properties is the optimal. La0.5Sr0.5Fe0.9975Ni0.0025O3 thin films annealing in argon thin films obtained optimal dielectric properties, the ?r is 1309, the tanδ is 0.061; in the air is the second, the ?r is 1172, the tanδ is 0.069; the oxygen is the worst, its ?r is 1137, the tanδ is 0.079.Cr doped LSF thin film can improve the ?r, along with the increase of the content of Cr(0.5, 1, 3mol%), the ?r of La0.5Sr0.5Fe1-x Crx O3 thin films firstly increased and then decreased, tanδ was first decreased and then increased. The optimal amount of Cr was is 1mol%(La0.5Sr0.5Fe0.99Cr0.01O3 dielectric thin films) have the optimal performance. The annealing atmosphere(air, oxygen, argon) has a great influence on the dielectric properties of La0.5Sr0.5Fe1-x Crx O3 thin films, dielectric properties of thin film LSF-Cr films are annealed in argon are bigger than air, oxygen annealing. La0.5Sr0.5Fe0.99Cr0.01O3 thin film’s ?r is 1207, the tanδ is 0.069; in the air second, the relative dielectric constant is 1125, the tanδ is 0.084. The La0.5Sr0.5Fe0.995Cr0.005O3 thin films annealed in O2 have the lower dielectric performance, the ?r is 957, the tanδ is 0.151.With the increase of the content of Co(0.2, 0.4, 0.6mol%), La0.5Sr0.5Fe1-x Cox O3 film’s ?r decreased, tanδ increased gradually. The optimal amount of Co was is 0.2mol%(La0.5Sr0.5Fe0.998Co0.002O3 dielectric thin films) have the optimal performance. Different annealing atmosphere(air, oxygen, argon) has a great influence on the dielectric properties of the films. Contrasting the optimal dielectric properties of samples with different annealing atmosphere, La0.5Sr0.5Fe0.996Co0.004O3 thin films annealing at argon obtained the optimal dielectric properties. the ?r is 1396, the tanδ value is 0.045; the La0.5Sr0.5Fe0.998Co0.002O3 thin film annealing at the air, the ?r is 1174, tanδ is 0.074; the dielectric properties of La0.5Sr0.5Fe0.998Co0.002O3 thin films annealed in O2 are relatively poor, the ?r is 887, the tanδ is 0.121.when the annealing atmosphere is oxygen or argon partly, along with the increase of Mn content, the ?r of La0.5Sr0.5Fe1-x Mnx O3 thin film first increased and then decreased, tanδ showed the opposite trend, and when the doping of Mn was 5mol%, have the optimal dielectric properties. Annealing in argon obtained the optimal dielectric properties of La0.5Sr0.5Fe0.95Mn0.05O3 thin films, the ?r is 1423, the tanδ is 0.056; Annealing in the oxygen is the worst relative, its ?r is 1083, the tanδ is 0.113.Compare the effects of the five elements substituents and three different annealing atmosphere on structure and dielectric properties of LSF-based film, we studied that Mg substituted let the dielectric properties of the film improve most. And the LSF film annealing in argon gas can got the optimization film. |
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