RUI: Magnetism and Phase Transitions of Mixed Magnetic Insulating Systems

他们将研究各种具有短程交换作用的混合磁铁和稀磁磁铁的磁性行为和相变。竞争自旋各向异性和/或竞争交换相互作用的效应特别令人感兴趣，特别是它们对T组分磁相图结构的影响。表现出四临界点或其他多临界点的新系统应该会出现，其中一些具有质的新特征。我们将研究新的绝缘自旋玻璃的例子，包括尚未在实验中实现的模型类的例子。为了加深他们对自旋玻璃普适性类的理解，我们将研究其非线性极化率，同时还将考察随时间变化的效应。还建议对某些Fe(III)二硫代氨基甲酸酯和双二硒代氨基甲酸酯化合物进行研究。人们的兴趣集中在描述这些不寻常的五坐标系中的磁序，确定零场分裂参数和交换相互作用，以及发现XY或Ising系统的新例子。方法将主要包括对单晶和多晶样品进行变温、变场磁化和磁化率测量。这项工作将对院系的研究环境产生重大影响，特别是在为本科生提供在学年和暑期进行研究的机会方面。这些经验将为以后的科学工作做好宝贵的准备。

They will examine magnetic behavior and phase transitions in a variety of mixed and dilute magnets with short-range exchange interactions. Effects of competing spin anisotropies and/or competing exchange interactions are of particular interest, especially their influence on the structure of T-composition magnetic phase diagrams. New systems exhibiting tetracritical or other multicritical points should emerge, some with qualitatively new features. New examples of the insulating spin glass will be examined, including cases of model classes not yet realized experimentally. The nonlinear susceptibility will be studied, in order to further their understanding of spin glass universality classes; time-dependent effects will also be examined. Work is also proposed on certain Fe(III) bisdithiocarbamate and bisdiselenocarbamate compounds. Interest centers on characterizing the magnetic ordering in these unusual pentacoordinate systems, determining zero-field splitting parameters and exchange interactions, and discovering new examples of XY or Ising systems. Methodology will consist primarily of variable temperature, variable field magnetization and susceptibility measurements on both single crystal and polycrystalline samples. This work will have a major impact on the departmental research environment, especially in opportunities afforded undergraduates for research during the academic year and during summers. Such experiences will be valuable preparation for later scientific work.