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

小行星9704110 该振动样品磁强计将用于研究富金属颗粒铁磁固体的磁性。 这些是纳米复合材料，其中存在含有不混溶的非晶相（例如，Al2O3）。 使用逾渗理论的语言，它们可以被描述为高于临界浓度，具有磁性相。 虽然近年来颗粒金属的研究热潮，但由于缺乏巨磁电阻效应，富金属材料在很大程度上被忽视。 虽然在研究过程中是自然的，但这种情况不应该持续下去;富含金属的系统在应用和基础科学中都提供了几种有希望的研究途径。 与逾渗转变以下的颗粒金属相比，这些材料既更容易研究，也更有技术前景。 这有两个主要原因：评估颗粒尺寸分布的影响没有困难，净磁化强度大得多，Tc可能远高于室温。 本提案将详细介绍对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，而第二个涉及可能的应用。 这些项目分别是：本文研究了杂质使磁相关长度减小时的磁相变，并对含杂质的硬磁合金的磁记录特性进行了评价。 该振动样品磁强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，其中存在含有不混溶的非晶相（例如，Al2O3）。 使用逾渗理论的语言，它们可以被描述为高于临界浓度，具有磁性相。 虽然近年来颗粒金属的研究热潮，但由于缺乏巨磁电阻效应，富金属材料在很大程度上被忽视。 虽然在研究过程中是自然的，但这种情况不应该持续下去;富含金属的系统在应用和基础科学中都提供了几种有希望的研究途径。 与逾渗转变以下的颗粒金属相比，这些材料既更容易研究，也更有技术前景。 这有两个主要原因：评估颗粒尺寸分布的影响没有困难，净磁化强度大得多，Tc可能远高于室温。 本提案将详细介绍对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，而第二个涉及可能的应用。 这些项目分别是：本文研究了杂质使磁相关长度减小时的磁相变，并对含杂质的硬磁合金的磁记录特性进行了评价。 ***

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. ***