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Design, Synthesis and Magnetic Properties of Micro and Nano-structured Iron Oxide

Author: GuoXiaoFang
Tutor: SunHuiYuan
School: Hebei Normal
Course: Condensed Matter Physics
Keywords: Micro and nano structures Surface morphology Growth Mechanism Magnetic properties
CLC: TB383.1
Type: Master's thesis
Year: 2010
Downloads: 51
Quote: 0
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Abstract


Iron oxide as a non-toxic , non-polluting green materials in many areas has important applications . In recent years, in order to obtain a different shape and properties of the iron oxide material , the development of a variety of preparation methods . This paper assisted method oxalate singular iron oxide nano- material has been subjected to a heat treatment to the the nanoscale iron coating on a glass substrate using magnetron sputtering preferred orientation , and its microstructure , the growth mechanism and magnetic properties of the preparation conditions made a systematic study of the relationship between . Main results are as follows: a (110) preferred orientation of nanoscale iron film dropwise addition of oxalic acid, and then subjected to a heat treatment in the atmosphere directly prepared polyhedral, tabular , flower -like structure of the iron oxide material . When the temperature is below 300 ℃ reaction , is not easy to form iron oxide ; 300-400 ° C is mainly of Fe3O4 ; product is higher than 500 ℃ α -Fe2O3 . Infiltration of oxalic acid method, a reaction temperature of 100-300 ° C , the heating rate of 10 ℃ / min , formed mainly uniformly ordered polyhedral structure ; reaction temperature of 400-600 ° C , the heating is slow , the sheet - like product morphology uniform . As the reaction temperature increases , the sheet-like product has a widened . Fe film is thicker, the easier the formation of a relatively large aspect rod product . Liquid using scanning probe microscopy mode , respectively, of the dropping of 0.75M oxalic acid and only dropping distilled water without heat treatment sample morphology test and found that the the iron membrane surface initial morphology is significantly different . Dropwise addition of distilled water only sample surface formed mainly spherical particles; while the dropwise addition of oxalic acid iron film formed on the surface of the particles having a nearly rhombic cross section . It was thus confirmed that the oxalic acid plays an important role in the formation of a rhombic cross section polyhedron . Low temperatures polyhedron and the formation of the flower -like structure nucleation - growth - gathered - self-assembly process , high temperature showings ( silk ) -like product formation follow the diffusion mechanism . To study the magnetic properties of the material and found that the coercivity first increases and then decreases as the reaction temperature increases , there is a great value at 300 ℃ ; saturation magnetization gradually decreases . Parallel to the film surface direction of the easy magnetization direction .

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