Development of: High Resolution, High Sensitivity Scanning Josephson Junction Microscope

这项建议是为了研制一种高分辨率、高灵敏度的磁场成像显微镜。该仪器将能够测量介观器件中电流产生的微小磁场(10-5G)、量子结构的磁性和器件内部电子的晶格态。该仪器将是第一台扫描约瑟夫森结显微镜(SJM)。它的场灵敏度将比传统的磁力显微镜高六个数量级，空间分辨率比扫描鱿鱼显微镜高一个数量级。为了建造这个工具，麻省理工学院几个小组的专业知识必须结合在一起。形成关键传感元件的约瑟夫森结(JJ)必须集成在原子力显微镜尖端，以便与样品足够接近。这一过程将需要开发一种微机械硅底座，JJ将在其上进行加工。一旦制造了传感元件，就必须将其集成到一个更大的仪器中，该仪器由低温冷却的压电级和电路组成，用于监测和放大来自JJ的信号。建成后，高场灵敏度和高空间分辨率的结合将允许研究超导体中的涡旋态，电路和生物系统中的电荷输运，介观磁体的磁态，以及电子指数的自旋态。最后，新型扫描探针显微镜的发展为交叉学科的教育提供了激动人心的机会。目前，从事器件加工、电路设计、介观器件物理和材料科学专业的学生都参与了核心技术的开发。

This proposal is for the development of a high resolution, high sensitivitymagnetic field imaging microscope. This instrument will allow for themeasurement of minute magnetic fields (10-5 G) generated by currents inmesoscopic devices, the magnetic properties of quantum structures and thespin states of electrons inside devices. The instrument will be the firstscanning Josephson junction microscope (SJM). It will have six orders ofmagnitude higher field sensitivity than conventional magnetic forcemicroscopy and an order of magnitude better spatial resolution thanscanning SQUID microscopy.In order to build this tool, the expertise of several groups at MIT must bebrought together. The Josephson junction (JJ) that forms the criticalsensing element must be integrated on an atomic force microscope tip inorder to be in sufficient proximity to the sample. This process willrequire the development of a micromechanical silicon submount onto whichthe JJ will be processed. Once the sensing element has been fabricated itmust be integrated into a larger instrument composed of cryogenicallycooled piezo-stages and circuits to monitor and amplify the signals fromthe JJ. When completed, the combination of high field sensitivity andhigh spatial resolution will allow for the study of vortex states insuperconductors, charge transport in circuits and biological systems, themagnetic state of mesoscopic magnets, and the spin state of electrons indevices.Finally, the development of a new scanning probe microscope offers excitingopportunities for interdisciplinary education. Already, students workingon device processing, circuit design, mesoscopic device physics andmaterials science have all participated in the development of the coretechnologies.