【作者】 张弘；

【导师】 贺德衍；

【作者基本信息】 兰州大学 ， 凝聚态物理， 2009， 博士

【摘要】 自旋电子学是一门新兴学科,是目前倍受关注的研究领域。众所周知,目前大部分的微电子器件、集成电路的处理单元等都是基于对电子电荷的调制,而基于电子自旋（轨道）磁性的信息存储、身份识别等在目前人类生活当中也具有相当重要的地位。自旋电子学的研究目的就是将电子的这两种性质结合起来。目前自旋电子学的主要研究内容包括自旋器件与材料两个方面。本论文对这两个方面的相关问题开展了研究,主要研究内容和取得的结果有:（1）纳米度域Co掺杂ZnO稀磁性半导体的制备研究。在H₂SO₄和C₂H₂O₄两种电解液中用直流恒电位阳极氧化技术二次氧化制备了孔径在10～60nm之间的系列多孔阳极氧化铝（AAO）模板,利用电化学沉积的方法在模板中沉积得到了Zn_99.35Co_0.65O纳米线。VSM测试证明所制备的Co掺杂ZnO具有明显的铁磁性质,EDS测试证明了Zn_xCo_1.xO的化学配比与反应溶液中各反应物的摩尔比例相一致。（2）Fe[001]/MgO[001]/Fe[001]磁隧道结多层薄膜的制备。采用低速交替溅射方法制备了具有极薄预溅射层的Fe/MgO/Fe隧道结。通过改变预溅射层中的Fe层和MgO层的厚度及样品的退火温度,实现了隧道结中Fe层和MgO层沿[001]方向的共同取向,检测了预溅射层厚度及样品退火温度对于薄膜结晶性质的影响,获得了预溅射层厚度及退火温度的最佳值以及高自旋极化电极。（3）自旋极化电流长程输运测试。利用溅射技术沉积了平面电极,并利用FIB技术对电极进行了刻蚀。水平Kerr效应测试证明得到了磁化强度方向反转。用染色电泳的方法在电极之间成功地连接了CNT,并实现了CNT的数量可控。利用楔形电极测试了实验用多壁CNT的电学性质,在对特殊条件下制备的器件原型的外加磁场电阻测试发现,当外加磁场到达250e时得到大约为15%的MR信号。更多还原

【Abstract】 Spintronics is a rising and attended research field presently.As well known,the basis of information technology is the charge of electron.Most of microelectronic device and processing unit in integrate circuit is based on the manipulation of charge in electronic circuit.And the magnetic property based on the spin of electron also possesses important role in passing economic life.For instance:information storage, identification and communication.The research purpose of spintronics is to combine this two properties of electron together.That means spin devices research and spin materials research.In this work,this two research objects all were studied and discussed.The main research contents just like follow:（1） The preparation of Co-doped ZnO diluted magnetic semiconductor in nano scale. Firstly,we prepared a series of porous anodic oxide aluminum template（diameter is from 10nm to 60nm） by DC constant voltage oxide technique in H2SO4 and C₂H₂O₄ electrolyte.Then Zn_99.35Co_0.65O nanowires were deposited in templates. The VSM testing proved the prepared Co-doped ZnO have distinct ferromagnetic property,and the EDS testing proved the proportion of element in Zn_xCo₍1-x_O is matched with the mol proportion of the reactants in solution.（2） The synthesis of Fe[001]/MgO[001]/Fe[001]magnetic tunnel junctions（MTJs） multilayer films.A series of Fe/MgO/Fe magnetic tunnel junctions were synthesized by low speed alternate sputtering,the testing results proved the different thickness of pre-sputtering layer has effect on the crystallographic properties of Fe/MgO/Fe tunnel junction.Meanwhile,the samples we fabricated were annealed in deferent temperature.The right annealing temperature can improve the crystallographic properties of tunnel junction.After XRD testing,we found the fabricated MTJs gained mutual[001]orientation of Fe and MgO after deposition of proper thickness pre-sputtering layer.At last,we found the optimal condition of the thickness of pre-sputtering layer and annealing temperature.The candidate of high spin-polarization electrodes was gained. （3） The characterization of long-distance transportation of spin current.The flat electrodes were deposited by alternate sputtering.The horizontal Kerr effect testing results demonstated the reversal of magnetization orientation.Then carbon nanotubes（CNTs） were connected between electrodes by dye electrophoresis method successfully.And the numbers of the connected CNT could be controlled also.In the MR testing,the 15%MR testing signal appeared when the external magnetic field reached 25 Oe.更多还原