磁性纳米粒子分散体中的偶极相互作用和退磁效应：引入平均场相互作用超顺磁体模型（MFISP模型）
Dipolar interaction and demagnetizing effects in magnetic nanoparticle dispersions: introducing the Mean Field Interacting Superparamagnet Model (MFISP Model)
摘要：
一个模型的目的是分析相互作用的超顺磁体。模型是建立在磁偶极相互作用和退磁平均场的概念。给出了有效退磁因子的表达式，可用于分析纳米粒子的非均匀空间分布。该表达式是与样品和簇形状相关联的退磁因子的函数，以及近邻纳米颗粒之间和簇之间的平均距离的函数，分别相对于这两种类型的对象中的每一种的特征尺寸。它解释了磁偶极相互作用的影响，如观察到的表观纳米粒子磁矩小于真实的。它示出，通过执行一组最小的实验测定，模型应用程序允许检索的内在属性，如磁矩和磁化率在没有相互作用。它还允许估计平均粒子间和团簇间的相对距离，以及与团簇形状相关的退磁因子。每个纳米粒子的磁偶极能量的表达式也来自。通过对文献报道结果和原始结果的分析，进行了模型试验。它们对应于分散在PEGDA-600聚合物和PVA铁凝胶中的磁铁矿颗粒。实验结果表明，当沿主方向测量棱柱形样品时，会出现不同的磁响应。从分析中检索到的内在性质和结构信息，与FESEM图像获得的信息非常一致。在所研究的样品中，发现纳米颗粒在几乎随机取向的簇中彼此紧密接触。团簇间平均相对距离在2.2和7.5之间变化，这取决于颗粒的体积分数。
英文摘要：
A model is developed with the aim of analyzing interacting superparamagnets. Model is built from magnetic dipolar interaction and demagnetizing mean field concepts. A useful expression for effective demagnetizing factors is achieved, which allows for the analysis of non uniform spatial distributions of nanoparticles. This expression is a function of demagnetizing factors associated with specimen and clusters shapes, and of the mean distances between near neighbor nanoparticles and between clusters, relative to the characteristic sizes of each of these two types of objects, respectively. It explains effects of magnetic dipolar interactions such as the observation of apparent nanoparticle magnetic-moments smaller than real ones. It is shown that by performing a minimum set of experimental determinations, model application allows retrieval of intrinsic properties, like magnetic moment and susceptibility in the absence of interactions. It also permits the estimation of mean interparticle and intercluster relative distances, and of demagnetizing factors associated with clusters shape. An expression for magnetic dipolar energy per nanoparticle is also derived. Model experimental test was performed by analysis of results reported in the literature and of original results. They correspond to magnetite particles dispersed in PEGDA-600 polymer, and in PVA ferrogels. Experimental results display different magnetic response when prism shaped specimens are measured along principal directions. Intrinsic properties and structural information were retrieved from the analysis, in excellent agreement with information obtained from FESEM images. In the studied samples nanoparticles were found to be in close contact to each other within almost randomly oriented clusters. Intercluster mean relative-distance was found to vary between 2.2 and 7.5, depending on particles volume fraction.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
