Phase Coherence and Dynamics in Superconductor Arrays and Unconventional Superconductors

w：\awards\awards96\num.doc 9705695货车哈林根本实验研究项目主要研究长程相位相干性在超导材料和器件中的作用。 这项工作是基于SQUID干涉测量技术的PI已经开发出检测单晶超导体样品中的序参量的相位;并在使用扫描 SQUID显微镜（SSM）。 三个研究领域 （1）使用SSM 到 研究 超导体中的涡旋位形和动力学 阵 (2)SQUID干涉测量法在确定重费米子超导体和有机体系序参量对称性中的应用 两种超导体 的 材料 显示出非常规配对的迹象(3)混合系统的磁成像，d波和s波岛的交替排列。 这个实验研究项目，在非常规类型的超导性研究的前沿，重点是超导体和超流体的"相位相干"性质。 超导体最有用的特性：超流体 （无损） 电 导电性， 和 超导量子干涉器件（SQUID）磁场传感器和快速逻辑元件都源于相位相干。最近发现， 相位相干 性能 的 高 TC 铜氧化物超导体 是 截然不同 从 那些 像铅和铌钛这样的传统超导体。该研究项目部分致力于其他类型超导体、有机金属和"重费米子"超导体的相位特性，这些超导体也可能表现出 非常规相行为。这项研究的一部分将利用扫描乌贼显微镜，它可以测量局部磁场的十亿分之一奥斯特（1/2奥斯特大约是地球磁场的水平），空间分辨率约为100微米。这项研究的结果可能包括不寻常的新 可能适用的效果或结构 在技术上。这个研究项目是跨学科的性质，涉及研究生谁将得到良好的培训，进入行业，政府或教育职位。 ***

w:\awards\awards96\num.doc 9705695 Van Harlingen This experimental research project focuses on the role of long- range phase coherence in superconductor materials and devices. The work is based on the SQUID interferometry techniques the PI has developed to detect the phase of the order parameter in single crystal superconductor samples; and on the use of a scanning SQUID microscope (SSM). Three areas of proposed research include: (1) Use of the SSM to study vortex configurations and dynamics in superconductor arrays. (2) Application of the SQUID interferometry methods to identify the order parameter symmetry in heavy fermion superconductors and in organic superconductors, both types of material showing indications of unconventional pairing. (3) Magnetic imaging of hybrid systems consisting, e.g.,of alternating arrays of d-wave and s-wave islands. %%% This experimental research project, at the forefront of research in unconventional types of superconductivity, focuses on the "phase coherence" property of superconductors and superfluids in general. The most useful properties of superconductors: the superfluid (lossless) electrical conduction, and the Superconducting Quantum Interference Device (SQUID) magnetic field sensors and fast logic elements, all arise from phase coherence. It has recently been found with high probability that the phase-coherent properties of the high Tc cuprate superconductors are strikingly different from those of conventional superconductors, like lead and NbTi. This research project is devoted in part to the phase properties of additional types of superconductors, organic metals and "heavy fermion" superconductors, which may also exhibit unconventional phase behavior. Portions of this research will utilize a Scanning Squid Microscope, which can measure local m agnetic fields at the level of one billionth of an Oersted (1/2 Oersted is about the level of the earth's magnetic field) with a spatial resolution of about 100 micrometers. Results from this research may include unusual new effects or structures which may find application in technology. This research project is interdisciplinary in nature and involves graduate students who will be excellently trained to enter positions in industry, government or education. ***