RUI - Magnetic Symmetry and Symmetry Analysis of Domains

这是一笔用于本科院校研究的拨款。对铁相转变中产生的畴结构的物理性质的理解和预测是基于对相关晶体对称性的性质和相互关系的分析。为了给畴对和畴孪生的分类提供依据，π推导出了磁性和非磁性的亚周期群并将它们制表。这项工作将继续并扩展到新的磁空间群表和确定磁空间群与磁亚周期群之间的关系，这是分析畴结构与其畴壁之间关系的基础。还将导出所有磁孪生定律，表示两个同时观察到的磁畴状态（磁畴对）之间的对称关系的组，并用于确定可以区分观察到的磁畴的物理性质。PI还将确定磁域对的分类，其中单个类中的所有磁域对可以通过同一组物理性质张量来区分，并确定在哪个铁相转变中出现这种磁域对。在领域工程的背景下，PI将对领域状态集进行分类，确定它们的对称性并预测它们的物理性质。本科生将参与这些研究项目。%%%这是一笔资助本科生在本科院校（RUI）进行研究的经费。研究的重点是将群理论制表并应用于涉及铁电体相变的问题。＊＊＊

This is a grant for Research at Undergraduate Institutions (RUI). The understanding and prediction of the physical properties of domain structures which arise in a ferroic phase transition are based on an analysis of the properties and interrelationships of the associated crystallographic symmetries. To provide a basis for the classification of domain pairs and domain twins, the PI has derived and tabulated both the magnetic and non-magnetic subperiodic groups. This work will be continued and extended with a new tabulation of the magnetic space groups and a determination of the relationship between the magnetic space groups and magnetic subperiodic groups which is fundamental for the analysis of the relationship between domain structures and their domain walls.Also to be derived will be all of the magnetic twin laws, groups that express the symmetry relationships between two simultaneously observed magnetic domain states (domain pair) and are used to determine physical properties that can distinguish between the observed magnetic domains. The PI will also determine a classification of magnetic domain pairs where all domain pairs in a single class can be distinguished by the same set of physical property tensors, and determine in which ferroic phase transition such magnetic domain pairs arise. In the context of domain engineering the PI will classify sets of domain states, determining their symmetry and predicting their physical properties.Undergraduate students will participate in these research projects.%%%This is a grant for research at an undergraduate institution (RUI) which involves the participation of undergraduate students. The focus of the research is on tabulating and applying group theory to problems involving phase transitions in ferroelectrics. ***