"Neutron Scattering, Transport, and Dilatometry Measurements of Magnetic Materials"

“磁性材料的中子散射、传输和膨胀测量”

• 批准号: 249706-2012
• 负责人: Adams, Carl
• 金额: $ 1.55万
• 依托单位: St. Francis Xavier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=547373
• 关键词: Neutron; Scattering; Transport; Dilatometry; Measurements

A very large fraction of our modern technology is based on materials and their properties, e.g., microprocessors, computer hard drives, light-emitting diodes. These materials allow for cost-effective, reliable devices. The useful properties are often based on some fundamental physics in the system. In the case of computer hard drives, a very small part of the drive acts as a permanent magnet, whose polarity can be switched by a write head and measured by a read head at extremely high speeds. The proposed research focuses on magnetic materials, that order in a large number of ways, often in a way that is more exotic than the computer hard drive. In these cases, we are still trying to figure out the details of the ordering and how it comes about. Understanding the magnetism in these systems is the primary goal of this research. This is important from a fundamental viewpoint, but also for possible applications. In many cases, these systems can undergo large changes of ordering with very small changes in temperature, magnetic field, or by adding dopants. In one of the materials, the magnetism can almost disappear by forming pairs of oppositely aligned magnets. In another, a change in magnetism makes a big change in the electrical conductivity, like a magnetic switch. Another material has a spiral type of order that is related to materials that do not have any electrical resistance. The research involves neutron scattering, which gives a lot of information about magnetism on an atom by atom or electron by electron scale, but is carried out at very large facilities. There are also measurements of the electrical resistance and direct measurements of sample expansion using sensitive equipment.

我们的现代技术很大一部分是基于材料及其特性，例如微处理器、计算机硬盘、发光二极管。 这些材料可实现经济高效、可靠的设备。 有用的属性通常基于系统中的一些基本物理原理。 就计算机硬盘驱动器而言，驱动器的一小部分充当永磁体，其极性可以通过写入头切换并通过读取头以极高的速度进行测量。 拟议的研究重点是磁性材料，这种材料以多种方式排列，通常比计算机硬盘驱动器更奇特。 在这些情况下，我们仍在试图弄清楚订购的细节以及它是如何产生的。 了解这些系统中的磁性是本研究的主要目标。 从基本角度来看，这很重要，而且对于可能的应用也很重要。 在许多情况下，这些系统可以通过温度、磁场或添加掺杂剂的微小变化来经历较大的有序变化。 在其中一种材料中，通过形成一对相反排列的磁体，磁性几乎可以消失。 另一方面，磁性的变化会导致电导率发生巨大变化，就像磁性开关一样。 另一种材料具有与不具有任何电阻的材料相关的螺旋类型的顺序。 这项研究涉及中子散射，它提供了有关原子或电子在电子尺度上的磁性的大量信息，但是在非常大的设施中进行的。 还可以使用敏感设备测量电阻和直接测量样品膨胀。