微波环行器用低维铁氧体的制备及性能研究

发布时间：2018-05-18 08:20

本文选题：微波环行器 + 铁氧体薄膜　；参考：《电子科技大学》2016年博士论文

【摘要】：随着电子信息和通讯技术的高速发展,电子器件不断的向多功能、小型化发展,这对电子材料的筛选、制备以及设计提出了更高的要求。环行器属于微波无源电子器件,利用铁氧体材料的非互易性能,可实现对电磁信号传播方向的调控。根据磁性器件的发展趋势,薄膜化、更多功能集成、工作频率高频化以及自偏置必将是磁性微波环行器的发展方向。六角M型钡铁氧体(BaFe_(12)O_(19),BaM)具有显著的高单轴各向异性特性而被业界人员任命为未来环行器实现高频以及自偏置的首选材料,同时钇铁石榴石铁氧体(Y3Fe5O12,YIG)具有显著的低铁磁共振线宽特性,因此低维BaM以及YIG的制备对实现环行器的小型化具有重要的意义。本论文的研究工作是围绕着微波环行器用高饱和磁化强度、高磁晶各向异性场以及高矩形比的低维BaM材料以及低铁磁共振线宽的低维YIG材料的制备进行展开。首先,分别在氧化铝、氧化镁以及硅基底上外延生长BaM薄膜,通过测试设备对其微观结构以及磁性能进行表征分析,探讨薄膜的磁性能与沉积参数的关联问题,并最终择出最佳薄膜沉积参数。其次在硅以及GGG基底上沉积制备亚微米厚度的YIG薄膜,探讨铁磁共振线宽扩宽的机理问题。然后尝试在多孔硅掩模板里生长铁氧体纳米线阵列膜,分析纳米线的生长机理及磁性能特性。最后利用脉冲激光沉积技术以及超薄氧化铝掩模板(AAO)在不同衬底上制备二维铁氧体纳米点阵列膜,分析点阵的性能。主要内容可分为以下四部分。1、BaM薄膜的制备以及性能的调控。(1)两步烧结法制备致密性达到98.6%,且晶粒直径仅为2.2mm的(33)a(44)靶材;((17))在氧化铝基底上研究分析了沉积参数与薄膜微观性能的关联问题,探讨了薄膜微观性能与磁性能的关联问题,并基于缓冲层Pt对薄膜的磁性能进行调控研究。最终在20 nm厚的Pt以及最佳沉积参数下制备出具有357 emu/cm3的饱和磁化强度、16.5 kOe的单轴各向异性场以及不足20%的矩形比的BaM薄膜;(3)在氧化镁基底上研究分析了退火温度以及缓冲层Pt对BaM薄膜结构以及磁性能的影响。研究缓冲层Pt在降低薄膜结晶温度以及阻隔元素扩散方面的作用。并研究发现低温长时间退火处理在薄膜结晶性以及磁性能方面都有重要的改善作用。最终在20 nm-Pt的缓冲层上、950 oC-10 h的退火条件下制备出Ms高达358 emu/cm3,单轴各向异性场16.5 kOe,矩形比50.2%的BaM铁氧体薄膜。(4)在硅基底上研究了缓冲层厚度对薄膜性能的影响,并最终在200nm-Pt缓冲层基础上,900 oC-3 h的退火条件下得到BaM薄膜具有Ms高达317 emu/cm3,68.6%的矩形比以及15 kOe的单轴各向异性场。(5)通过对不同基底上的BaM薄膜进行一阶反转曲线测试并对结果进行分析对比,得到氧化铝以及氧化镁基底上得到的BaM薄膜以多畴晶粒结构为主,而硅基底上的BaM薄膜以单畴晶粒结构为主,并且晶粒之间的相互作用场大小满足关系Al_2O_3MgOSi。2、YIG薄膜的的制备以及铁磁共振线宽的研究。(1)采用分步烧结技术制备高质量YIG靶材。(2)提出了采用多层缓冲层法,调控YIG薄膜的铁磁共振特性。通过引入CeO2/YSZ以及三层(YAG/YAIG/YIG)低温缓冲层,成功的将硅基底上YIG薄膜的铁磁共振线宽降低到53 Oe,同时将YIG薄膜的最大无裂纹厚度提高到500 nm。(3)在GGG基底上研究制备亚微米级厚度的YIG薄膜,探讨薄膜的铁磁共振特性与薄膜微观性能的关系问题。通过铁磁共振谱中的多峰以及与膜厚的关系问题分析出薄膜内存在拥有不同有效场的共振区域。并且通过不同磁场角度下共振谱得到亚微米级薄膜拥有7 Oe的本征铁磁共振线宽以及最大25 Oe的非本征铁磁共振线宽。3、铁氧体纳米线阵列膜的制备及其性能研究。(1)分别采用无电沉积铜颗粒法以及自组装金点阵法制备多孔硅掩模板。并最终经过两步刻蚀出孔洞直径与间距皆为500 nm的多孔硅掩模板。(2)利用溶胶凝胶法分别在多孔硅模板里生长BaM以及钴铁氧体(CoFe2O_4,CFO)纳米线阵列膜。微观结构显示BaM以及CFO纳米线阵列的直径约为200 nm。磁性能上,BaM纳米线阵列表现出各向同性特性,矫顽力以及矩形比分别为2560 Oe以及0.6。CFO纳米线阵列也表现出各向同性特性,通过一阶反转曲线图分析,矫顽力分布在1000 Oe出现的概率最高,纳米线阵列之间存在一定的相互作用力。4、铁氧体纳米点阵膜的制备以及性能的研究。(1)YIG纳米点阵膜的制备及磁性能的研究。分别在硅以及GGG基底上制备YIG纳米点阵。微观形貌上看,点阵的直径与超薄AAO的直径一致,大约在350 nm。YIG点阵具有比连续薄膜更大的矫顽力特性。YIG点阵的铁磁共振谱出现多峰以及线宽展宽现象,可能源于纳米点阵的微观结构的不均匀性和动态磁化过程的非一致转动。(2)BaM点阵的制备及磁性能的研究。分别在硅以及氧化铝基底上制备钡铁氧体点阵。X-射线衍射仪显示氧化铝基底上易获得高取向点阵,点阵相比于连续薄膜具有更高的矩形比特性,同时一阶反转曲线图显示BaM点阵具有单畴特性。点阵具有颗粒间的相互作用力小于连续薄膜特性。
[Abstract]:With the rapid development of electronic information and communication technology, the electronic devices are constantly developing to multifunction and miniaturized. This has put forward higher requirements for the screening, preparation and design of electronic materials. The circulator is a microwave passive electronic device, and the non reciprocal properties of ferrite materials can be used to control the propagation direction of electromagnetic signals. According to the development trend of magnetic devices, thin film, more functional integration, high frequency frequency and self bias will certainly be the development direction of magnetic microwave circulators. The six angle M type barium ferrite (BaFe_ (12) O_ (19), BaM) has significant high uniaxial anisotropy and is appointed by industry personnel for high frequency and self bias of future circulators. The first choice material, while the yttrium ferric pomegranate ferrite (Y3Fe5O12, YIG) has a significant low ferromagnetic resonance linewidth characteristic, so the preparation of low dimensional BaM and YIG is of great significance for the realization of the miniaturization of the circulator. The research work of this paper is about the high saturation and magnetization of the microwave circulator, the high magnetic anisotropy field and the high moment. The preparation of low dimensional BaM material with shape ratio and low dimensional YIG material of low ferromagnetic resonance line width are carried out. First, BaM thin films are grown on alumina, Magnesium Oxide and silicon substrate respectively. The microstructure and magnetic properties of the thin films are characterized and analyzed by testing equipment. The relationship between the magnetic properties of thin films and the deposition parameters is discussed, and the most of them are discussed. The best thin film deposition parameters are selected. Secondly, the submicron thickness YIG film is deposited on the silicon and GGG substrates. The mechanism of the width expansion of the ferromagnetic resonance line is discussed. Then the ferrite nanowire array film is grown in the porous silicon mask, and the growth mechanism and magnetic properties of the nanowires are analyzed. Finally, the pulsed laser deposition is used. Technology and ultra-thin alumina mask (AAO) are used to prepare two-dimensional ferrite nanometers on different substrates and analyze the properties of the lattice. The main contents can be divided into four parts:.1, BaM film preparation and performance control. (1) two step sintering method is used to prepare 98.6% density, and the grain diameter is only 2.2mm (33) a (44) target; (17) in (17)) The relationship between the deposition parameters and the microstructure of the film was studied and analyzed on the alumina substrate. The relationship between the microstructure and magnetic properties was discussed. The magnetic properties of the films were regulated based on the buffer layer Pt. The saturation magnetization of 357 emu/cm3 was finally prepared under the 20 nm thick Pt and the optimum deposition parameters. 16.5 The uniaxial anisotropic field of kOe and the BaM thin film with a rectangular ratio of less than 20%; (3) the effects of annealing temperature and buffer layer Pt on the structure and magnetic properties of BaM films on the Magnesium Oxide substrate were investigated and analyzed. The effect of buffer layer Pt on the crystallization temperature of the film and the diffusion square surface of the barrier elements was studied. The treatment has an important improvement in the crystallinity and magnetic properties of the film. At 20 nm-Pt buffer layer and 950 oC-10 h annealing conditions, the effects of Ms as high as 358 emu/cm3, uniaxial anisotropy field 16.5 kOe, rectangular ratio 50.2% BaM ferrite film. (4) the effect of the thickness of buffer layer on the film properties is studied on the silicon substrate. Finally, on the basis of 200nm-Pt buffer layer, under the annealing condition of 900 oC-3 h, the BaM thin film has a rectangular ratio of up to 317 emu/cm3,68.6% and the uniaxial anisotropic field of 15 kOe. (5) the first order inversion curve of the BaM film on the different substrates is tested and the results are analyzed and compared, and the alumina and the Magnesium Oxide substrate are obtained. The BaM film is dominated by multi domain grain structure, and the BaM film on the silicon substrate is dominated by single domain crystal structure, and the interaction field between the grains satisfies the relationship Al_2O_3MgOSi.2, the preparation of the YIG film and the ferromagnetic resonance line width. (1) the high quality YIG target is prepared by the step sintering technology. (2) the application of the high quality YIG target is made. The ferromagnetic resonance characteristics of YIG films are regulated by the multilayer buffer layer method. By introducing CeO2/YSZ and three layer (YAG/YAIG/YIG) low temperature buffer layer, the ferromagnetic resonance line width of the YIG film on the silicon substrate is reduced to 53 Oe, and the maximum non crack thickness of the YIG film is raised to 500 nm. (3) to study the submicron thickness YIG on GGG substrate. The relationship between the ferromagnetic resonance characteristics of the film and the microstructure of the film is discussed. Through the multiple peaks in the ferromagnetic resonance spectrum and the relationship between the film thickness and the film thickness, the film has a resonant region with different effective fields. And the intrinsic ferromagnetic resonance of the submicron thin film with 7 Oe is obtained by the resonance spectrum of different magnetic fields. The line width and the maximum 25 Oe of the non intrinsic ferromagnetic resonance line width.3, the preparation and properties of the ferrite nanowire array film. (1) the porous silicon mask was prepared by the electroless copper particle method and the self assembled gold dot matrix method. The porous silicon mask with the diameter and spacing of the holes was 500 nm, and (2) using dissolution. BaM and cobalt ferrite (CoFe2O_4, CFO) nanowire arrays are grown in the porous silicon template respectively. The microstructure shows that the diameter of BaM and CFO nanowire arrays is about 200 nm. magnetic energy, the BaM nanowire array shows isotropic properties, the coercive force and the moment ratio are 2560 Oe and 0.6.CFO nanowire arrays respectively. According to the isotropic characteristics, the probability of the coercive force distribution at 1000 Oe is the highest by the first order reversal curve diagram. There is a certain interaction force.4 between the nanowire arrays, the preparation of the ferrite nano lattice film and the study of its properties. (1) the preparation and magnetic properties of the YIG nanometers are studied on silicon and GGG substrates, respectively. YIG nanometers are prepared. The micromorphology shows that the diameter of the lattice is in accordance with the diameter of the ultra-thin AAO. The ferromagnetic resonance spectrum of the ferromagnetic resonance spectrum of the.YIG lattice with greater coercivity than that of the continuous film appears at about 350 nm.YIG, which may arise from the inhomogeneity of the microstructures and the dynamic magnetization process of the nanolattice. Non uniform rotation. (2) the preparation and magnetic properties of BaM lattice. The barium ferrite lattice.X- ray diffractometer on silicon and alumina substrate shows high orientation lattice on the alumina substrate, and the lattice has a higher rectangular ratio than that of the continuous film. The first order reversal curve shows that the BaM lattice has a single domain at the same time. The lattice interaction between particles is smaller than that of continuous film.
【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TM277;TN621

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