Acquisition of a Vibrating Sample Magnetometer for the Characterization of Nanocomposite Magnetic Materials

获取用于表征纳米复合磁性材料的振动样品磁力计

• 批准号: 9704110
• 负责人: Andrew Gavrin
• 金额: $ 7.15万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 1999-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9704110&HistoricalAwards=false
• 关键词: Acquisition; Vibrating; Sample; Magnetometer; Characterization

9704110 Gavrin This vibrating sample magnetometer will be used to perform research on the magnetic properties of metal-rich granular ferromagnetic solids. These are nanocomposite materials in which there exists a continuous meal matrix with inclusions of an immiscible nonmagnetic phase (e.g., Al2 O3). Using the language of percolation theory, they may be described as well above the critical concentration, with a percolating magnetic phase. While recent years have seen an upsurge in granular metals research, metal-rich materials have been largely ignored due to the absence of the giant magnetoresistance effect. Although natural in the course of research, this state of affairs should not persist; metal rich systems offer several promising avenues of research, both in applied and fundamental science. Compared with granular metals below the percolation transition, these materials are both easier to study and more technologically promising. There are two principle reasons for this: There is no difficulty evaluating the effects of a particle size distribution, and The net magnetization is much greater, and Tc may be well above room temperature. This proposal will detail two studies of these materials. The first deals with the fundamental nature of magnetism in disordered systems, while the second addresses a possible application. Respectively the projects are: A study of the magnetic phase transition as the nonmagnetic impurities reduce the magnetic correlation length, and An evaluation of potential magnetic recording characteristics of hard magnetic alloys with nonmagnetic impurities. %%% This vibrating sample magnetometer will be used to perform research on the magnetic properties of metal-rich granular ferromagnetic solids. These are nanocomposite materials in which there exists a continuous meal matrix with inclusions of an immiscible nonmagnetic phase (e.g., Al2 O3). Using the language of percolation theory, they may be described as well above t he critical concentration, with a percolating magnetic phase. While recent years have seen an upsurge in granular metals research, metal-rich materials have been largely ignored due to the absence of the giant magnetoresistance effect. Although natural in the course of research, this state of affairs should not persist; metal rich systems offer several promising avenues of research, both in applied and fundamental science. Compared with granular metals below the percolation transition, these materials are both easier to study and more technologically promising. There are two principle reasons for this: There is no difficulty evaluating the effects of a particle size distribution, and The net magnetization is much greater, and Tc may be well above room temperature. This proposal will detail two studies of these materials. The first deals with the fundamental nature of magnetism in disordered systems, while the second addresses a possible application. Respectively the projects are: A study of the magnetic phase transition as the nonmagnetic impurities reduce the magnetic correlation length, and An evaluation of potential magnetic recording characteristics of hard magnetic alloys with nonmagnetic impurities. ***

9704110 Gavrin 这种振动样品磁力计将用于研究富含金属的粒状铁磁固体的磁性。 这些是纳米复合材料，其中存在连续的金属基质，其中包含不混溶的非磁性相（例如 Al2 O3）。 使用渗流理论的语言，它们可以被描述为也高于临界浓度，具有渗流磁相。 尽管近年来粒状金属研究兴起，但由于缺乏巨磁阻效应，富含金属的材料在很大程度上被忽视。 虽然这种情况在研究过程中很自然，但不应持续存在；富含金属的系统在应用科学和基础科学方面提供了几种有前景的研究途径。 与渗流转变以下的粒状金属相比，这些材料更容易研究，在技术上也更有前景。 造成这种情况的主要原因有两个：评估粒度分布的影响并不困难，净磁化强度要大得多，Tc 可能远高于室温。 该提案将详细介绍这些材料的两项研究。 第一个涉及无序系统中磁性的基本性质，而第二个则涉及可能的应用。 这些项目分别是：研究非磁性杂质减少磁相关长度时的磁相变，以及评估含有非磁性杂质的硬磁合金的潜在磁记录特性。 %%% 该振动样品磁力计将用于研究富含金属的粒状铁磁固体的磁性。 这些是纳米复合材料，其中存在连续的金属基质，其中包含不混溶的非磁性相（例如 Al2 O3）。 使用渗流理论的语言，它们可以被描述为也高于临界浓度，具有渗流磁相。 尽管近年来粒状金属研究兴起，但由于缺乏巨磁阻效应，富含金属的材料在很大程度上被忽视。 虽然这种情况在研究过程中很自然，但不应持续存在；富含金属的系统在应用科学和基础科学方面提供了几种有前景的研究途径。 与渗流转变以下的粒状金属相比，这些材料更容易研究，在技术上也更有前景。 造成这种情况的主要原因有两个：评估粒度分布的影响并不困难，净磁化强度要大得多，Tc 可能远高于室温。 该提案将详细介绍这些材料的两项研究。 第一个涉及无序系统中磁性的基本性质，而第二个则涉及可能的应用。 这些项目分别是：研究非磁性杂质减少磁相关长度时的磁相变，以及评估含有非磁性杂质的硬磁合金的潜在磁记录特性。 ***