Magnetic Behavior and Phase Transitions of Selected Pure, Dilute and Mixed Magnets

我们将考察各种具有短程交换作用的纯磁、稀磁和混合磁系统的详细磁行为，特别是与磁相变相关的行为。纯材料之所以有趣，是因为：一些是一种新的过渡金属系列的成员，其中某些成员表现出非平衡行为，其中一个是铁磁性的，是一种罕见的普适类的潜在成员；还有一些显示出非常大的零场分裂的迹象。对绝缘体中自旋玻璃行为的研究特别重要，其中几种拟议的混合磁体可以在绝缘体中表现出这种行为，而几种拟议的混合磁体可以表现出这种行为。其中之一是一种潜在的新型自旋玻璃，它可能发生在稀释先前研究的新型铁磁体时发生。即使除了自旋玻璃的形成，这种稀释铁磁体的行为也是一个重要的问题。其中两个混合系统具有三元性质，即它们包含两个以上的组分。在绝缘材料中，这种系统几乎没有被研究过。混合磁体将包含相互竞争的交换作用、相互竞争的各向异性、不同的自旋值或这些的某种组合。确定磁性相图是这项工作的一个主要目标，它显示了有序化温度与组成和相稳定区域的关系。一些理论预测的相图类型还有待观察。还将获得几个系统的超高场磁化数据，无论是纯的还是混合的；这将产生关于材料中临界场和零场分裂的新信息。%要检查的化合物包括简单过渡金属盐的新型一水合物，它们具有某些新的结构或磁性特征。对这些体系的研究将促进材料科学的目标，如阐明结构-性质关系和开发具有新性能的材料。一个主要的影响将是为理科本科生提供机会，在工业高度优先的领域获得前沿研究课题的经验。

The detailed magnetic behavior, especially that associated with magnetic phase transitions, of various pure, dilute and mixed magnetic systems with short-range exchange interactions will be examined. The pure materials are interesting because: some are members of a new transition metal series certain members of which exhibit nonequilibrium behavior, one is ferromagnetic and a potential member of a rare universality class; and others show signs of very large zero-field splittings. The study of spin glass behavior in insulators is of particular importance, and several of the proposed mixed magnets could exhibit such behavior in insulators is of particular importance, and several of the proposed mixed magnets could exhibit such behavior. One of these is a potential new type of spin glass which may occur on diluting a previously studied ferromagnet of novel type. Even apart from spin glass formation, the behavior of a ferromagnet of this kind with dilution is an important problem. Two of the mixed systems are ternary in character, that is they contain more than two components. Such systems are virtually unstudied among insulating materials. The mixed magnets will contain either competing exchange interactions, competing anisotropies, different spin values, or some combination of these. Determination of magnetic phase diagrams, showing the dependence of ordering temperature on composition and regions of phase stability, is a major objective of this work. Some theoretically predicted phase diagram types are yet to be observed. Very high field magnetization data will also be obtained for several systems, both pure and mixed; this will yield new information on critical fields in the materials and on zero-field splittings.%%%The chemical compounds to be examined included novel monohydrates of simple transition metal salts that exhibit certain novel structural or magnetic features. Studies of these systems will further such materials science goals as elucidation structure-property relationships and developing materials with new properties. A major impact will be the opportunities afforded undergraduate science students to gain experience with frontier research topics in a field of high priority to industry.