RUI: Magnetism and Phase Transitions of Mixed Magnetic Insulating Systems

RUI：混合磁绝缘系统的磁性和相变

• 批准号: 8906337
• 负责人: Gary DeFotis
• 金额: $ 8.94万
• 依托单位: College of William and Mary
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-06-01 至 1992-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8906337&HistoricalAwards=false
• 关键词: RUI; Magnetism; Phase; Transitions; Mixed

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.

他们将研究磁行为和相变在一个 具有短程交换的各种混合和稀释磁体 交互. 竞争自旋各向异性的影响和/或 竞争交换相互作用是特别感兴趣的， 特别是它们对T成分结构的影响 磁相图 新系统表现出四临界或 其他多关键点应该出现，一些与质量 新功能。 绝缘自旋玻璃的新例子将是 包括尚未实现的模型类的情况 实验性的 将研究非线性极化率， 为了进一步理解自旋玻璃的普遍性 类;还将检查与时间相关的影响。 工作是 也建议在某些Fe（III）bisdithiocarbamate和 双二硒代氨基甲酸酯化合物。 兴趣集中在 描述了这些不寻常的 五坐标系，确定零场分裂 参数和交换互动，并发现新的 XY或Ising系统的示例。 方法将包括 主要是可变温度，可变磁场磁化 和磁化率测量的单晶和 多晶样品 这项工作将对 部门研究环境，特别是在 为本科生提供的研究机会， 学年和暑假期间。 这些经验将是 为以后的科学工作做了宝贵的准备。