STM-fabricated Magnets and Their Influence on Semiconductor Electronics

磁性纳米颗粒阵列作为致密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”器件中的集成是所提出工作的基础。这项工作主要集中在磁性颗粒的生产和表征上，无论是单个的，还是排列成小群的，或者是大阵列的。使用扫描隧道显微镜（STM-MOCVD）和高分辨率电子束光刻技术的微金属有机气相沉积将用于在III-V型半导体异质结构上制造这些系统。直径低至10nm的Fe， Co和Ni颗粒将被制造出来。通过由半导体异质结构制成的霍尔交叉来感应粒子的磁场，可以间接探测它们的磁性行为。在梯度计配置的测量将扩展超越其目前的限制阵列和低温到单粒子和室温。此外，还将利用具有变场能力的磁力显微镜（MFM）在室温下进行补充直接观察。粒子间的相互作用将通过实验和数值模拟进行研究。磁性和电子测量相结合的良好表征结构将被用来制定一个物理图像的磁性动力学在缩小的长度尺度和这种磁性结构对半导体电子学的影响将被探索。现代技术在很大程度上依赖于微加工，特别是微电子技术。这项工作的目标是制造有规则排列的纳米（nm）大小的磁性颗粒；（一个原子的直径约为0.3纳米），并研究它们的磁性以及它们对半导体导电性的影响。这种磁性和电子特性的整合被认为会导致下一代微电子，即所谓的“自旋电子”设备。在提出的工作中，磁性颗粒，无论是单独或排列在小群体，或在大阵列将被制造和研究。迄今为止，用于此类研究的实验技术仅限于阵列和非常低的温度。目前研究的目标之一是超越这些限制，将研究扩展到单粒子和室温。磁性和电子测量相结合的特征结构将用于制定一个物理图像的磁性动力学在缩小长度尺度和这种磁性结构对半导体电子学的影响。本科生和研究生以及博士后研究助理将参与本研究。他们将因此获得凝聚态物理和材料科学前沿领域的技能和知识。这将使他们成为本世纪未来几十年科学/技术劳动力中富有成效的成员

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.***