铁氧体薄膜的电化学制备及多铁性磁电复合薄膜性能研究

发布时间：2018-03-19 01:16

本文选题：钴铁氧体　切入点：枝晶状　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：同时具有磁性能、电性能以及磁电耦合效应的材料叫做多铁性磁电材料。多铁性磁电材料可分为单相磁电材料和复合磁电材料。单相的磁电材料是本身就具有铁电性、磁性以及磁电耦合效应的多铁性材料。复合磁电材料是由具有压电特性的铁电材料与具有磁致伸缩效应的磁性材料组成的。复合磁电材料中的磁性部分多由铁氧体材料提供。众所周知,不同的铁氧体中,尖晶石结构的钴铁氧体作为作为一种硬磁材料具有高的矫顽力,良好的饱和磁化强度,显著的化学稳定性以及机械硬度而被人们广泛关注,而同样,由于其较高的磁致伸缩效应有望用来与铁电材料复合形成磁电耦合复合材料。此外,近年来,如何控制生产工艺而沉积出不同形态的钴铁氧体薄膜也开始成为了人们的关注热点。本文研究的是在Pt/Ti/SiO2/Si基片上利用电化学沉积并阳极活化的方法制备出了阵列型枝晶状的钴铁氧体(CoFe2O4,CFO)薄膜。首先,在室温下,利用电化学沉积法在硫酸铁和硫酸钴的电解液中制备出了钴铁合金(CoFe2,CF)薄膜。因此,实验中对于制备钴铁氧铁薄膜的的晶体结构,微观形貌以及薄膜的性能所需的实验条件进行分析。发现了一项有趣的现象,很多论文中报道出的利用电化学沉积法制备出CF合金薄膜后,再通过在空气中烧结出平整均匀的CFO薄膜这一结果不同,我们发现,当阳极活化处理的CF合金薄膜通过在空气环境中进行烧结后,可以得到一种柱状的甚至枝晶状结构的CFO薄膜。阳极处理在很多论文里面是起到氧化作用的,可以将CF合金薄膜氧化成为CFO薄膜。而我们发现,阳极处理这一过程并不是氧化作用,对于得到CFO薄膜不是必须的一个过程,但却对于得到柱状甚至枝晶状铁氧体薄膜时一个很重要的过程,并且铁氧体薄膜的柱状结构可以通过调节阳极活化的参数得到不同厚度的薄膜。X射线衍射(XRD)仪和X射线光电子能谱(XPS)用来表征钴铁氧体薄膜的晶体结构,原子力显微镜(AFM)和扫描电子显微镜(SEM)用来表征薄膜的微观形貌。振动样品磁强计(VSM)也被用来测量薄膜的磁滞回线。同时铁电体电滞回线测量仪等电学测试仪器被用于复合薄膜的电学测试,电化学工作站及氙灯用于薄膜的光学测试。
[Abstract]:Materials with magnetic properties, electrical properties and magnetoelectric coupling effects are called ferroelectric materials. Multiferromagnetic materials can be divided into single-phase magnetoelectric materials and composite magnetoelectric materials. The single-phase magnetoelectric materials are ferroelectric in their own right. Multiferroelectric materials with magnetic and magnetoelectric coupling effects. Composite magnetoelectric materials are composed of ferroelectric materials with piezoelectric properties and magnetic materials with magnetostrictive effects. Body material supply. As is known to all, Among different ferrites, cobalt ferrite with spinel structure has attracted much attention as a hard magnetic material with high coercivity, good saturation magnetization, remarkable chemical stability and mechanical hardness. Because of its high magnetostrictive effect, it is expected to be used to form magnetoelectric coupling composites combined with ferroelectric materials. In addition, in recent years, How to control the production process and produce cobalt ferrite thin films of different shapes has also become a hot topic. In this paper, the electrochemical deposition and anodic activation on Pt/Ti/SiO2/Si substrates have been studied to fabricate the array type of cobalt ferrite thin films. Dendritic cobalt ferrite CoFe2O4 (CFO) thin films. CoFe2CF-CoFe2C thin films were prepared in the electrolyte of ferric sulfate and cobalt sulfate by electrochemical deposition at room temperature. Therefore, the crystal structure of ferric cobalt ferrite thin films was studied in the experiment. The micromorphology and the experimental conditions required for the properties of the films were analyzed. An interesting phenomenon was found. Many papers reported that CF alloy films were prepared by electrochemical deposition. The results of sintered even CFO thin films in air are different. It is found that when the anodic activated CF films are sintered in air, A columnar or even dendritic CFO thin film can be obtained. Anodic treatment can oxidize CF alloy film to CFO film in many papers. Anodic treatment is not an oxidation process, which is not a necessary process for the preparation of CFO films, but an important process for obtaining columnar or even dendritic ferrite films. The columnar structure of ferrite thin films can be used to characterize the crystal structure of cobalt ferrite films by adjusting the parameters of anodic activation to obtain thin films with different thickness by means of X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPSs). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to characterize the micromorphology of the films. Vibratory sample magnetometers (VSMs) were also used to measure the hysteresis loops of the films. At the same time, electrical instruments such as ferroelectrics hysteresis loop measuring instruments were used to measure the hysteresis loops of the films. For electrical testing of composite films, Electrochemical workstation and xenon lamp are used for optical test of thin film.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2

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