Ni添加量对FeCoNiB-SiO_2薄膜电磁性能的影响

采用RF溅射工艺制备了FeCoNiB-SiO2系薄膜。研究了Ni添加量对该种薄膜微结构和电磁性能的影响。结果表明,添加适量的Ni有利于FeCoNiB-SiO2薄膜获得优良的微波电磁性能。通过控制Ni的添加量,可以得到在GHz频段同时具有高磁导率和高损耗的薄膜样品,其磁导率实部μ'和虚部μ"在0.5~2.0GHz的宽频带范围内分别大于240和100,在2.1GHz处更是均大于400,其电阻率也达到了868×10–6?·cm。该薄膜可应用于微波吸收材料或抗电磁干扰的设计中。     

Nd掺杂对BiFeO3薄膜微结构和电学性能的影响

采用化学溶液方法,在LaNiO3/Si(100)衬底上生长了Nd掺杂的BiFeO3薄膜.XRD分析结果表明,随着Nd掺杂量的增加,薄膜晶格变小,Nd掺杂量为20%时,薄膜出现杂相.介电测试表明,随着Nd掺杂量的增加,介电常数和损耗减小,Nd掺杂量为2%的薄膜表现出很强的介电色散现象并出现介电损耗弛豫峰,其符合类德拜模型特征.随着Nd掺杂量增加,薄膜的漏电流减小,在低电场下,电流输运遵从SCLC模型,在高场下,电流输运遵循Poole-Frenkel模型.分析结果表明Nd掺杂对薄膜微结构和电学性能有显著影响.     

CuO掺杂量对LSMO/NiCuZn复合材料微波特性的影响

采用固相反应法制备了La0.67Sr0.33MnO3/(Zn0.6Fe0.4)[Ni0.4-xCuxFe1.6]O4(LSMO/NiCuZn)铁氧体复合材料。研究了CuO掺杂量对复合材料在1MHz～1.8GHz频段下的复磁导率频谱特性和复介电常数频谱特性的影响。结果表明:CuO掺杂量的增加(x=0.05～0.20),提高了复合材料磁谱与介电谱的虚部,增加了材料的磁损耗与介电损耗,提高了材料的吸波性能。当CuO的掺杂量x为0.20时,复合材料磁导率和介电常数的虚部分别达到27和107。     

磁性薄膜微波电磁参数测试方法研究进展

Fe、Co基合金薄膜具有高磁导率、高损耗等特点,可实现微波的宽频带吸收,是一类具有很大发展潜力的新一代吸波材料。磁性膜的复磁导率对吸波性能有重大影响,因而在吸波材料研究中提出了磁谱测量的紧迫要求。综述了国内外磁性薄膜电磁参数微波测量方法,主要介绍了磁性薄膜电磁参数的谐振腔法、双线圈法和传输线法,并对当前研究中存在的问题进行了讨论。     

FeNHf磁性薄膜微结构中太赫兹波损耗的抑制

基于半导体微纳工艺设计并制备了一种FeNHf磁性薄膜的镜像四环非对称太赫兹微结构,测试了薄膜磁性能和微结构太赫兹波传输特性.结果 表明FeNHf薄膜在0.5 GHz时在难轴方向的磁导率为410,共振频率为1.48 GHz,磁各向异性场强度为31.88 Oe(1 A·m-1 =4π×10-3 Oe).通过比较基于FeNH...     

H_3BO_3掺杂对Co_2Z基磁介天线基板材料影响研究

为研制适用于915 MHz RFID天线小型化应用需要的磁介基板材料,采用固相反应烧结法研究了H3BO3掺杂对(Ba0.5Sr0.5)3Co2Fe24O41铁氧体微观形貌和磁介性能的影响。通过研究发现,H3BO3掺杂能很好地促进Co2Z铁氧体的低温烧结成相。同时,H3BO3掺杂也有利于抑制Co2Z铁氧体晶粒生长。随着H3BO3掺杂量的增多,材料体系的磁导率持续下降,而介电常数先上升后下降。当掺杂H3BO3的质量分数为4%,材料体系在915MHz时可获得磁导率为2.45,介电常数为10.41,磁损耗正切为0.057,介电损耗正切为0.005的综合磁介性能。     

电磁场与微波技术

O442007050944影响磁性薄膜微波磁谱测量精度的因素/江建军,彭显旭,杜刚,张秀成,何华辉(华中科技大学电子科学与技术系)//微波学报.―2006,22(5).―35～38.针对铁磁薄膜复磁导率在微波频段的测量,该文采用了一种利用短路微带线进行扫频的新方法。在介绍其测量过程的基础上,重点     

V_2O_5掺杂改善锰锌铁氧体组织及性能的研究

采用传统陶瓷法制备锰锌铁氧体,研究了不同V_2O_5掺杂量对锰锌铁氧体烧结试样微观结构及磁性能的影响。获得了适用于电磁加热的高性能Mn Zn铁氧体材料。结果表明,适量的掺杂V_2O_5能显著改善材料的微观结构,并且能明显提高材料的磁性能。当V_2O_5掺杂量为质量分数0.05%时,样品拥有最佳的磁性能,其振幅磁导率、比总损耗及矫顽力分别为1704,30.36 W/kg,4.8 A/m(100 m T,100 k Hz)。     

膜态组合对掺杂型负磁伸纳米级耦合膜磁性能的影响

采用离子束溅射沉积法,通过溅射Sm-Fe-B合金靶、Ni-Fe靶及纯Fe靶,在锡青铜和盖玻片衬底上溅射沉积由B掺杂的Sm-Fe-B负磁致伸缩薄膜与Ni-Fe、纯Fe组合的纳米级耦合薄膜材料。通过采用LK-500激光微位移传感器测量薄膜自由端偏转量,用交变梯度磁强计测试薄膜的磁滞回线,研究不同比例的膜态组合及不同软磁材料耦合的膜态组合对薄膜的磁致伸缩性能及软磁特性的影响。实验结果表明:磁致伸缩层与软磁层的比例为3∶1时的磁致伸缩性能、软磁特性最佳;且在磁致伸缩层与软磁层耦合的比例为3∶1基础上,通过改变耦合软磁层材料种类,薄膜的磁致伸缩性能与软磁特性可以得到进一步改善。     

退火对非晶态碲镉汞薄膜微结构和光敏性的影响

对射频磁控溅射生长的非晶态碲镉汞(a-MCT)薄膜在真空状态下进行退火,并通过X射线衍射(XRD)技术指出原生及低于125℃退火后的MCT薄膜均为非晶态.采用双体相关函数g(r)和电学测试系统研究了退火对a-MCT薄膜微结构和光敏性的影响.结果表明:经110℃,115℃和120℃退火后的a-MCT薄膜短程有序畴Rs由退火前的13.9 分别增大至17.9 、20.8 和26.2 ;光敏性则由原来的1.17,分别增加至退火后的2.01、2.67和4.25.     

低温烧结平面六方铁氧体的非线性磁性研究

介绍了低温烧结Y型平面六方铁氧体的非线性磁性能。采用固相反应法制备样品,使用HP4284A,配合HP42841A直流源,测试外加磁场对软磁铁氧体高频磁导率的调制特性。研究表明,随外磁场强度增加,材料的磁导率呈非线性下降。定义了磁性可调率,用以表征外磁场调制下磁导率的改变量,此参数与材料本身的磁性能和显微结构密切相关。随Zn含量升高,材料的磁导率和可调率同时上升,可调率最高可达50%以上。     

核壳型磁性颗粒微波磁导率模拟与实验研究

采用有效媒质理论模拟和实验验证的方法,研究了核壳型磁性颗粒的微波磁导率。结果表明:核壳结构有利于提高微波下颗粒的复磁导率,2GHz时,其实部比氧化后的颗粒提高6%~12%,虚部提高15%~30%。片状椭球形核壳结构优于球形核壳结构,2GHz时,20nm壳层厚的片状颗粒的复磁导率为4.85–1.71i,而同壳层厚的球状颗粒为4.55–1.31i。在核壳结构的颗粒中,壳层厚度薄有利于改善磁导率。     

可调谐微机电电感(续)(英文)

<正>3 Magnetic Core Tuned Inductor Magnetic core tuned inductor is tuned based on the magneto impedance effect[32].As the bias DC magnetic field is applied along to the axis of the inductor body,the transverse permeability of the soft magnetic layer can be changed to achieve the tunability of the inductance.In order to design tunable microinductors for microwave communication systems,such as the frequency range over 1 GHz,     

应用于射频范围的软磁薄膜研究进展

探讨了获得具有优良高频电磁性能的软磁薄膜的合适工艺条件。指出薄膜的性能主要取决于薄膜的成分、微观组织、磁致伸缩系数、残余应力状态、有无软磁底层、外加磁场溅射沉积和后续磁场热处理等因素。以Fe70Co30为基的软磁薄膜和Fe(Co)-X-N纳米晶软磁薄膜主要应用于要求高饱和磁化强度的器件如磁头中,磁性纳米颗粒膜具有高的电阻率因而趋肤深度较大,有望应用于高频微磁器件如微电感、微变压器的磁芯中。     

Influence of substrate on the high-frequency permeability of thin iron films

The ferromagnetic resonance (FMR) spectra of thin metallic films obtained by magnetron deposition on polymeric and ceramic substrates are investigated in the strip line at frequencies of 0.13–12 GHz via frequency and external magnetic field sweeping. The influence of mechanical stresses on the FMR spectra of films deposited on an elastic (polyethylene rephthalate) substrate is discussed. The magnetostriction contribution to the anisotropy field of a film, as well as the influence of tensile stresses on the quasi-static permeability and FMR frequency, is estimated. It is demonstrated that the microwave properties of a thin metallic film are also specified by the properties of the substrate with such a film. A distinction in the magnetic properties of films with the same composition, which are deposited on different substrates, is explained in terms of the magnetostriction effect.     

Influence of the magnetoelastic effect on the microwave magnetic properties of Fe-N thin films

The microwave permeability of nitrogen-doped iron films deposited on a flexible lavsan substrate has been experimentally investigated. The measurements were performed with the use of a coaxial transmission line. The coaxial samples were coiled from a flexible film in two different ways: with the deposited layer facing outward and with the deposited layer facing inward. It has been found that the measured frequency dependences of the permeability of the two samples strongly differ. A comparison is made between the microwave permeabilities measured in the coaxial transmission line and in a strip transmission line, in which planar samples were used. It is shown that investigation of the influence of the magnetoelastic effect on the magnetic properties at microwave frequencies can provide additional information on the magnetic structure of the material.     

Synthesis Method and Absorption Application of Nanocrystalline Alloy Flakes

The soft magnetic Fe-Si-B nanocrystalline/ amorphous flakes were fabricated by ball milling from the elemental powders and annealing the amorphous precursor, respectively. The microstructure, magnetic and microwave properties were evaluated by different synthesis methods. By computation, ball-milled Fe78Si13B9 flakes demonstrated potential appfication in absorption.     

Mechanical Strain‐Tunable Microwave Magnetism in Flexible CuFe2O4 Epitaxial Thin Film for Wearable Sensors

Purely mechanical strain‐tunable microwave magnetism device with lightweight, flexible, and wearable is crucial for passive sensing systems and spintronic devices (noncontact), such as flexible microwave detectors, flexible microwave signal processing devices, and wearable mechanics‐magnetic sensors. Here, a flexible microwave magnetic CuFe₂O₄ (CuFO) epitaxial thin film with tunable ferromagnetic resonance (FMR) spectra is demonstrated by purely mechanical strains, including tensile and compressive strains, on flexible fluorophlogopite (Mica) substrates. Tensile and compressive strains show remarkable tuning effects of up‐regulation and down‐regulation on in‐plane FMR resonance field (H_r), which can be used for flexible tunable resonators and filters. The out‐of‐plane FMR spectra can also be tuned by mechanical bending, including H_r and absorption peak. The change of out‐of‐plane FMR spectra has great potential for flexible mechanics‐magnetic deformation sensors. Furthermore, a superior microwave magnetic stability and mechanical antifatigue character are obtained in the CuFO/Mica thin films. These flexible epitaxial CuFO thin films with tunable microwave magnetism and excellent mechanical durability are promising for the applications in flexible spintronics, microwave detectors, and oscillators.