Preparation of Ferromagnetic Nano-dot system and Its Magneto-Resistance

为了研究纳米材料的（自旋相关）电学性质，我们研究了纳米电极的制备、透射电子显微镜（TEM）专用附件的设计以及铁磁纳米粒子系统和纳米线的量子电导（QC）。在TEM中成功地进行了纳米结构的生产和导电路径的选择。1.纳米电极的制备：采用溅射法，以金刚石颗粒为掩模，可重复制备出具有纳米级尖端、长度为几十μm的纳米电极。2.纳米导电实验用TEM支架的设计与制作：制作了用于测量纳米点间纳米电流的TEM支架。保持器中可装载两个电极。奈米光 ...更多信息 3.有限数量Fe纳米粒子的电学测量：以厚度为10 nm的Fe-SrF_2薄膜为样品，测量了Fe纳米粒子嵌入SrF_2中的库仑阻塞效应。样品通过Au对电极附着，在室温下进行I-V测量。当接触面积小于700nm^2时，检测到0.4V的库仑阻塞。Au和Fe纳米线的量子电导：在TEM中研究了非磁性Au和铁磁性Fe纳米线。在这两种情况下，识别出具有半整数步长的QC。这一现象的出现受到断丝速度、磁场和偏置电压的影响。通过适当选择实验条件，使丝材呈现半整数阶跃的时间保持在1秒以上。这是足够长的时间来研究导线形状和QC之间的关系。少

For the study of (spin dependent) electric properties of nano materials, the production of nano-electrodes, the design of special attatchment for transmission electron microscopy (TEM) and the quantum conductance (QC) of ferromagnetic nano-particle systems and nano-wires were investigated. The production of nano-structures and selection of the conduction paths were successfully carried out inside TEM. The set of results will contribute to the future research on the spin dependent conduction of nano-structured materials.1.Production of Nano-Electrodes : By the sputtering method using diamond particles as the mask, electrodes having nano-scaled tip and the length of several tens of μm could reproducibly prepared. Using these electrodes, conduction experiments inside TEM became possible.2.Design and Production of TEM Holders for Nano-Conduction Experiments : TEM holders to measure the nano-current between nano-dots were produced. Two electrodes can be loaded in the holder. Nano-manufactun … More ng and adequate selection of measuring positions were realized in nano-scale.3.Electric Measurements of Limited Number of Fe Nano-Particles : Using the 10nm thick Fe-SrF_2 films as the sample where Fe particles are embedded in SrF_2, the Coulomb blockade effect was detected. The sample was attached by the Au counter electrode, I-V measurements were performed at room temperature. When the contact area was less than 700nm^2, the Coulomb blocade of 0.4V was detected. The number of particles in this area is about 10.4.Quantum Conductance of Au and Fe Nano-Wires : Nano-wies of non-magnetic Au and ferro-magnetic Fe were studied inside TEM. In both cases, QC with half integer steps was recognized. The appearance of this phenomenon was influenced by the broken speed of wires, the magnetic field and the bias voltage. By adequate selection of experimental conditions, the wire showing the half integer step was kept more than 1 second. This is long enough to study the relationship between the wire shape and QC. Less