STM-fabricated Magnets and Their Influence on Semiconductor Electronics

磁性纳米颗粒阵列作为高密度磁存储介质的潜在用途以及它们在半导体和金属自旋电子器件中的集成是拟议工作的基础。这项工作集中在磁性颗粒的生产和表征上，这些颗粒可以是单独的，也可以是以小群或大阵列排列的。利用扫描隧道显微镜(STM-MOCVD)和高分辨率电子束光刻技术，在III-V半导体异质结上制备了这些系统。将制造出直径小于10 nm的Fe、Co和Ni颗粒。它们的磁性行为将通过由半导体异质结构制成的霍尔十字感应粒子的磁场来间接探测。梯度计配置中的测量将超越目前对阵列和低温的限制，扩展到单个粒子和室温。此外，还将使用具有变场能力的磁力显微镜(MFM)在室温下进行互补的直接观测。粒子间的相互作用将通过实验和数值模拟来研究。本课程将结合磁学和电子学的测量，在较小的长度范围内描绘磁动力学的物理图景，并探讨这种磁性结构对半导体电子学的影响。现代技术在很大程度上依赖于微制造，特别是微电子学。这项工作的目标是在半导体结构上制备规则排列的纳米尺寸(Nm)的磁性颗粒(原子直径约为0.3 nm)，并研究它们的磁性以及它们对半导体电导率的影响。这种磁性和电性的结合被认为将导致下一代微电子，也就是所谓的自旋电子器件。在拟议的工作中，将制造和研究单独或以小组形式排列或以大阵列形式排列的磁性颗粒。到目前为止，用于此类研究的实验技术仅限于阵列和非常低的温度。本研究的目标之一是超越这些限制，将研究扩展到单个粒子和室温。对表征良好的结构的磁测量和电子测量的结合将被用来描述在缩减的长度尺度内的磁动力学的物理图景以及这种磁结构对半导体电子的影响。本科生和研究生以及博士后研究助理将参与这项研究。因此，他们将获得凝聚态物理和材料科学前沿领域的技能和知识。这些将使他们能够在本世纪的下一个几十年成为科学/技术劳动力的富有成效的成员。

The potential utility of arrays of magnetic nanoparticles as dense magnetic storage media as well as their integration in semiconducting and metallic 'spintronic' devices is the basis for the proposed work. The effort concentrates on the production and characterization of magnetic particles either individually or arranged in small groups, or large arrays. Micro-metal-organic vapor deposition using scanning tunneling microscopy (STM-MOCVD) and high-resolution e-beam lithography will be used to fabricate these systems on III-V semiconductor heterostructures. Fe, Co, and Ni particles, with diameters as low as 10 nm will be fabricated. Their magnetic behavior will be probed indirectly by sensing the magnetic fields of the particles through Hall crosses fabricated from the semiconductor heterostructures. Measurements in a gradiometer configuration will be extended beyond their present limitations to arrays and low temperature to single particles and to room temperature. Moreover, complementary direct observations at room temperature will be made using a magnetic force microscope (MFM) with variable field capability. Interparticle interactions will be investigated experimentally as well as by numerical simulations. The combination of magnetic and electronic measurements on well-characterized structures will be used to formulate a physical picture of magnetic dynamics within reduced length scales and the influence of such magnetic structures on semiconductor electronics will be explored.%%%Modern technology relies heavily on micro-fabrication and specifically on microelectronics. The goal of the proposed work is to fabricate regularly arranged magnetic particles of the size of nanometers (nm); (the diameter of an atom is about 0.3 nm) onto semiconductor structures and to study their magnetic properties as well as their influence on the electrical conductivity of the semiconductor. Such integration of magnetic and electronic properties is believed to lead to the next generation of microelectronic, so-called 'spintronic', devices. In the proposed work magnetic particles, either individually or arranged in small groups, or in large arrays will be fabricated and studied. The experimental techniques that have been used in such investigations have so far been limited to arrays and to very low temperatures. One of the goals of the present research is to go beyond these limits and extend the studies to single particles and to room temperature. The combination of magnetic and electronic measurements on well-characterized structures will be used to formulate a physical picture of magnetic dynamics within reduced length scales and the influence of such magnetic structures on semiconductor electronics. Undergraduate and graduate students, as well as post doctoral research associates will participate in this research. They will thereby acquire skills and knowledge in a forefront area of condensed matter physics and materials science. These will enable them to be productive members of the scientific/technological workforce for the next few decades of this century.***