New Nuclear Magnetic Resonance Techniques for the Study of Incommensurate Insulators and Incommensurate Glasses

9624962 Ailion NMR（和NQR）技术用于研究超大拓扑的超低扩散。PI将进一步发展这些缺陷，并应用于检测结构不相称绝缘和不相称玻璃中调制波的扩散。这些技术是基于测量的磁化衰减在不相应拓宽的核磁共振线形。此外，将发展旋转框架弛豫时间技术来测量四极核的慢运动。这些技术将用于阐明从完美的不对称晶体到不对称玻璃转变过程中这种运动的性质。本项目开发的技术应适用于其他拓扑缺陷的运动，如变形固体中的位错、磁体中的畴壁、超导磁通线、电荷和自旋密度波以及层状结构中的层状边界。核磁共振（NMR）技术将得到进一步发展，并应用于研究固体中大型块状缺陷的超低运动，这是其他技术无法检测到的。然而，最近由首席研究员开发的一种新技术可以检测到比传统技术慢几个数量级的运动。特别地，这些方法将应用于特定缺陷的运动。称为调制波，它存在于一类特殊的无序物质（称为不相称）中，其性质介于完美晶体和玻璃之间。这项研究涉及到完美晶体和无序物质之间的转变以及玻璃的性质。所获得的见解可能对理解磁体和超导体的性质很重要，并且新技术应该适用于广泛不同的固态系统中其他大规模缺陷的运动。＊＊＊

9624962 Ailion NMR (and NQR) techniques for the study of the ultraslow diffusion of large topological. defects will be further developed by the PI and applied to detecting the diffusion of the modulation wave in structurally incommensurate insulating and incommensurate glasses. These techniques are based on measurements of the magnetization decay over the incommensurately broadened NMR lineshape. In addition, rotating-frame relaxation time techniques will be developed for measuring the slow motions of quadrupolar nuclei. These techniques will be applied to elucidating the nature of such motions during the transition from a perfect incommensurate crystal to an incommensurate glass. The techniques developed in this project should be applicable to motions of other topological defects such as dislocations in deformed solids, domain walls in magnets, superconducting flux lines, charge and spin density waves, and layered boundaries in layered structures. %%% Nuclear magnetic resonance (NMR) techniques will be developed further and applied to the study of the ultraslow motions of large massive defects in solids, which can not be detected by other techniques. However, a novel technique, recently developed by the principal investigator, can detect motions that are several orders of magnitude slower than can be observed by the conventional techniques. In particular, these methods will be applied to the motions of a particular defect. called the modulation wave, which exists in a special class of disordered material (called incommensurate), which has properties intermediate between that of a perfect crystal and a glass. This research touches on the transition between perfect crystals and disordered matter as well as on the nature of glasses. The insight gained may be important in understanding the properties of magnets and superconductors, and the new techniques should be app licable to motions of other large-scale defects in widely different solid state systems. ***