Noise Investigations of Condensed Matter Systems

凝聚态系统的噪声研究

• 批准号: 8922967
• 负责人: Michael Weissman
• 金额: $ 32万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1993-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8922967&HistoricalAwards=false
• 关键词: Noise; Investigations; Condensed; Matter; Systems

Most materials exhibit slow fluctuations, with a broad distribution of characteristic rates, in a variety of electrical, mechanical, magnetic, and optical parameters. Despite the ubiquity of a simple form (1/f) for the frequency spectrum of such fluctuations, a wide variety of mechanisms are involved, as has been demonstrated in past experiments. These fluctuations are of interest for two general reasons. First, they limit the performance of a variety of sensors and devices. Second, they provide a useful tool to study fundamental properties of materials, especially the poorly understood types of materials known as glasses, which exhibit partially frozen random structures. They are using electrical, optical and magnetic fluctuation techniques to investigate ordinary glasses, glassy metals, spin glasses, magnetic materials with random domain structures, and other systems. Their particular focus is on how frozen random structures emerge from fluid random structures as temperature is lowered, and on what type of unfrozen modes remain at very low temperatures.

大多数材料在各种电气、机械、磁性和光学参数方面表现出缓慢的波动，具有广泛的特征速率分布。 尽管这种波动的频谱普遍存在简单形式（1/f），但正如过去的实验所证明的那样，其中涉及多种机制。 这些波动之所以令人感兴趣有两个一般原因。 首先，它们限制了各种传感器和设备的性能。 其次，它们提供了一个有用的工具来研究材料的基本特性，特别是人们知之甚少的玻璃材料类型，这种材料表现出部分冻结的随机结构。 他们利用电、光和磁涨落技术来研究普通玻璃、玻璃态金属、自旋玻璃、具有随机畴结构的磁性材料和其他系统。 他们特别关注的是随着温度降低，冻结的随机结构如何从流体随机结构中出现，以及在非常低的温度下保持何种类型的未冻结模式。