Mo衬底厚度对Ni-Mn-Ga形状记忆合金薄膜形貌及磁性能的影响

采用射频磁控溅射法制备不同厚度Mo衬底的Ni-Mn-Ga薄膜,采用扫描电子显微镜(FE-SEM)、原子力显微镜(AFM)、磁力显微镜(MFM)、振动样品磁强计(VSM)以及X射线衍射仪(XRD)对其形貌及磁性能进行观测和分析。实验发现,制备的Mo衬底Ni-Mn-Ga薄膜经退火后为T型马氏体结构,且当Mo衬底厚度在0~200 nm范围内变化时,其饱和磁化强度及居里温度呈现先减小后增大的趋势。当Mo衬底厚度约为100 nm时饱和磁化强度和居里温度具有最低值。薄膜表面颗粒直径随着Mo厚度的增大而减小,但在Mo厚为100 nm时出现增大。     

预拉伸量对倾斜溅射制备的柔性CoFeB薄膜性能的影响

通过在单向预拉伸开的聚二甲基硅氧烷(PDMS)上倾斜溅射CoFeB获得柔性CoFeB薄膜,采用光学显微镜、原子力显微镜(AFM)、振动样品磁强计(VSM)、矢量网络分析仪等表征其结构形貌和磁性能.结果表明,柔性CoFeB薄膜具有周期性的褶皱表面形貌,其横切面类似于正弦曲线,可用正弦曲线的波长和振幅来对薄膜的表面形貌进行描述.同时,该薄膜表现出单轴磁各向异性,易磁化方向垂直于预拉伸方向,且各向异性场的大小与预拉伸量相关.该磁各向异性来自于周期性的表面形貌和倾斜溅射.此外,该薄膜具有优良的高频磁性能,其起始磁导率和铁磁共振频率都与预拉伸量相关.这种具有周期性表面形貌的柔性CoFeB薄膜有望应用于柔性微波磁性器件中.     

(FeCo/CoNbZr)n多层软磁薄膜的结构与磁性能

利用磁控溅射制备纳米晶单轴各向异性(FeCo/CoNbZr)n多层软磁薄膜,通过CoNbZr层的加入来细化FeCo颗粒。这种组合而成的多层膜矫顽力低,单轴各向异性明显,各向异性等效场Hk高,热稳定性优良,非常适合应用于超高密度磁记录头。     

Cr、Fe和Co掺杂对NiMnGa马氏体相变和磁性能的影响

用电弧熔炼和甩带快淬的方法制备了NiMnGa基磁性形状记忆合金。研究了Cr、Fe和Co元素掺杂对磁性形状记忆合金NiMnGa的马氏体相变和磁性的影响。结果表明,在Ni50Mn33Ga17中用少量Cr替代Ni,马氏体相变温度随着Cr的增加而下降,而居里温度则升高,在NiCrMnGa中进一步掺杂Fe或Co都可以进一步降低马氏体相变温度并提高居里温度,马氏体相变温度的变化基本上遵循随电子浓度降低而降低的规律;此外,在NiMnGa中用Cr取代Ni会使得马氏体相和母相的铁磁交换作用同时增强,进一步在NiCrMnGa中掺杂Co对提高母相磁化强度更为有利,而掺杂Fe则对抑制马氏体相磁化强度增加更为有利。     

膜厚对FeCoAlON薄膜的静态与动态磁性的影响

采用射频磁控溅射法在Si(100)基片上沉积了不同氮分压和不同厚度的(Fe70.6Co29.4)88.2Al11.8-ON薄膜,研究了膜厚对5%氮分压沉积的薄膜静态与动态磁性的影响。当FeCoAlON薄膜的厚度较小时,薄膜表现出面内单轴磁各向异性,当薄膜厚度增加到210 nm时,薄膜出现了条形畴。动态磁性研究显示,对于面内单轴磁各向异性以及条形畴结构的FeCoAlON薄膜,都表现出优异的高频响应。特别地,对于具有条形畴结构的FeCoAlON薄膜,其磁谱曲线表现为多峰共振的特点。     

Giant magnetoresistance and magnetic anisotropy of Co9Fe/Cu/Co9Fe multilayer thin films on an MgO(110) substrate

Magnetoresistive effects have been investigated using Co₉Fe/Cu/Co₉Fe that were deposited on an MgO(110) substrate by ion beam sputtering with a 21-A-thick CU layer and with various thicknesses of the Co₉Fe films. The influence of a 50-A-thick Fe buffer layer has also been investigated. In addition to a cubic symmetry anisotropy (K₁), an in-plane uniaxial magnetic anisotropy (K_u) was induced, which easy axis is parallel to the (110) plane of the MgO substrate and the (001) plane with and without the 50-A-thick Fe buffer layer, respectively. The magnetoresistance (MR) ratio decreased monotonically with increasing thickness of the Co₉Fe films from 25 A to 70 A. A maximum MR ratio of 11.5 percent was obtained at room temperature. With increasing magnetic field, the MR ratio reached a plateau gradually after a steep drop at small magnetic fields without the Fe buffer layer. It reached a plateau rapidly at small magnetic fields with the Fe buffer layer. By considering both K_u and K₁, these behaviors can be accounted for by the magnetization processes involved.     

固相烧结法制备的Co_3O_4和Fe_2O_3磁性纳米颗粒

采用一种纳米颗粒的新型制备方法,即固相烧结方法,成功制备出单分散的Co_3O_4和Fe_2O_3磁性纳米颗粒。利用金属前驱体粉末混合在NaCl介质中高温下分解金属原子在NaCl颗粒上聚集长大,在空气中烧结氧化形成纳米颗粒。NaCl介质既作为纳米粒子成核和长大的基底,又作为隔离介质防止纳米颗粒在高温加热过程中出现烧结团聚现象。在制备过程中除了金属前驱体和NaCl,没有其他试剂使用。通过XRD、TEM、VSM等对制备出的Co_3O_4和Fe_2O_3纳米颗粒进行了物相结构和成分、微观形貌及磁性能的表征。结果表明,制备出的Co_3O_4和Fe_2O_3纳米颗粒颗粒尺寸小,结晶性好,且尺寸分布均匀。     

Ba 3 Co 2 Fe 24 O 41 /polyimide composites with magnetic and dielectric properties

Ba3Co2Fe24O41(Co2Z)/polyimide(PI) composites were synthesized via in-situ polymerization process, using the micron-sized Co2Z particles prepared by the solid-state reaction. X-ray diffractometer...     

Effect of static magnetic field on cell migration

The effect of a magnetic field on cells has long been investigated, but there are few quantitative investigations of the migration of cells. Cell migration is important as one of the fundamental activities of the cell. This study proposes a method to evaluate quantitatively the cell diffusion constant and the effect of a static magnetic field on cell migration. The cell lines are neuroblastoma (NG108‐15), fibroblastoma (NIH/3T3), and osteoblastoma (MC3T3‐E1). The static magnetic field of 30 or 120 mT is impressed by a permanent magnet in a vertical or horizontal direction to the dish. It is shown that the cell diffusion constant can represent the cell migration as the cell activity. It is found that the cell migration is enhanced by exposure to the magnetic field, depending on the kind of cell. It is conjectured that the static magnetic field affects cell migration, which is downstream of the information transmission. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(2): 46– 52, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20203     

厚度对Ni_(25)Fe_(75)-ZnO颗粒膜阻尼因子和软磁特性的影响

采用磁控溅射制备了(Ni_(25)Fe_(75))-ZnO颗粒膜,研究了其高频动态磁性与薄膜厚度的关系,用Landau-Lifshitz-Gilbert方程计算出阻尼因子,并用一个幂函数拟合与外场的关系曲线。实验结果和拟合结果表明,动态磁化时有效阻尼系数αeff和内禀阻尼系数αint均随着样品厚度减小而增大。αint和αeff变化的物理起源应该与微结构的不均匀性、薄膜与衬底之间的界面效应和薄膜中的混杂物有关。     

Spray pyrolysis of La0.6Sr0.4Co0.2Fe0.8O3-δ thin film cathodes

Spray pyrolysis has been used to prepare La_0.6 Sr_0.4Co_0.2Fe_0.8O_3-δ thin film cathodes for solid oxide fuel cell (SOFC) applications. The films are polycrystalline with nano-meter sized grains and less than 1 μm in thickness. Deposition parameters for film deposition have been established. The ratio of deposition temperature to solvent boiling point is found to be the most important processing parameter that determines whether a crack free homogeneous and coherent film is obtained. The morphology can be tailored by the deposition parameters. Annealing at 650^∘C for four hours in air results in coherent films of the desired perovskite phase. The films are potential cathodes for thin film micro-solid oxide fuel cells.     

空间级太阳电池阵用底片胶性能研究

空间级太阳电池阵用底片胶由硅橡胶和白炭黑组成,挥发份满足空间级胶粘剂要求,优良的电绝缘性能。在空间环境下,具有足够的粘接强度;长期处于真空、高低温交变环境下保证胶无脱层,足够的绝缘电阻,对太阳电池无裂片影响,并对聚酰亚胺膜及银箔起到防原子氧的作用,是一种综合性能优良的空间级硅橡胶。