Nuclear probes of magnetic order

稀土磁铁现在无处不在，被用于电动机和执行器，任何地方都可以将电力转化为运动。例子包括磁盘驱动器中的电机，移动磁盘和读/写头，便携式电动工具（钻、锯、驱动器等）中的电机，汽车上的遥控门锁。它们涉及到我们现代技术的方方面面。实现这一革命的材料是稀土/铁化合物Nd 2Fe 14 B。这是在20世纪80年代早期发现的，当时我参与了快速淬火液态金属的基础研究。 在我的工作中，我试图了解事物如何变得有磁性-它们的磁矩来自哪里-以及它们如何排列-一旦形成，这些瞬间如何选择在磁性材料中排列。虽然我的工作主要是基础性的，但正确理解这些基本问题对于开发新的高性能磁性材料至关重要。 在接下来的五年里，我将专注于一组稀土基材料，这些材料被广泛认为是“禁区”，或者至少是非常难以研究的。然而，由于我与加拿大中子束中心的科学家合作开发的技术，我们已经能够开放这些材料进行更详细的研究。我将研究基于钐、铕和镱的边缘磁性材料，这些材料的磁矩刚刚形成，很容易受到材料化学变化的影响。我还将研究钆化合物的非常明确的时刻，在那里实验困难，以前排除了详细的研究。

Rare earth magnets are now ubiquitous, being used in motors and actuators anywhere electricity is converted into motion. Examples range from motors in disc drives, moving both the disc and the read/write head, motors in portable power tools (drills, saws, drivers, etc...), remote door locks on cars. They touch every aspect of our modern technology. The material that enabled this revolution is the rare earth/iron compound Nd2Fe14B. This was discovered in the early 1980s as part of fundamental research on rapidly quenched liquid metals in which I was involved. In my work I seek to understand how things become magnetic - where their magnetic moment comes from - and how they order -- how, once the moment has formed, those moment choose to arrange themselves in a magnetic material. While my work is primarily fundamental in nature, a proper understanding of these basic issues is essential to the development of new, high performance magnetic materials. Over the next five years I will be concentrating on a group of rare earth based materials that are widely regarded as "off limits" or at least very difficult to study. However, as a result of techniques that I developed in collaboration with scientists at the Canadian Neutron Beam Centre, we have been able to open these materials to more detailed study. I will be looking at marginal magnetic materials based on samarium, europium and ytterbium where the magnetic moments are just forming and are easily affected by changes in materials chemistry. I will also be looking at very well defined moments on gadolinium compounds where experimental difficulties had previously precluded detailed study.