磁各向异性纳米结构的尺寸、微结构与磁转变温度内在关联机制研究

项目名称： 磁各向异性纳米结构的尺寸、微结构与磁转变温度内在关联机制研究

项目编号： No.11474174

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 王军

作者单位： 宁波大学

项目金额： 95万元

中文摘要： 当磁性材料的几何尺寸接近或小于相关特征物理长度时，尺寸效应会影响磁性材料的磁转变温度等重要磁物理参量，使其表现出明显区别于相应体材料的特性。目前，针对磁性参数的尺寸效应的研究对象主要是纳米薄膜和纳米颗粒，而具有各向异性的纳米结构（环形、管等）的磁转变温度等与尺寸、形貌、微结构、基片或包裹的界面等深层次相关联的物理机制研究较少。 本项目拟设计和制备不同尺寸的纳米环、管等各向异性复杂纳米结构材料，探讨这类纳米结构体系中的几何尺寸、微结构（阳离子占位、半径等）与其磁各向异性、磁翻转、磁转变温度等磁性参量之间的内在联系及普适性，探讨这类相关纳米结构的尺寸效应表达式中的标定指数，并利用蒙特卡罗模拟结合有限标度方法建立相应的理论模型。本项目的研究成果将对理解磁各向异性纳米结构材料的磁转变温度的尺寸效应的内在物理机制，丰富磁性微纳结构器件物理研究的方法和理论都具有重要的指导意义。

中文关键词： 纳米结构；磁转变温度；各向异性；铁氧体；尺寸效应

英文摘要： When the size of the magnetic material is close to or smaller than the size of the magnetic characteristic parameters,the small size effect of the nanostructures can affect important physical parameters，such as magnetic transition temperature. This leads to significantly different characteristics from those of the bulk material. Currently, international studies about the size effect of the physical parameters mainly focused on the nanofilms and nanoparticles, fewer studies reported the physical mechanisms about the relationship between magnetic phase transition temperature, size, morphology, microstructure, and interface of novel nanostructuressuch as nanorings, nanotubes and so on. This project intends to design and fabricate different sizes of nanorings and nanotubes, explore the intrinsic link between magnetic properties and geometry size and microstructure (cation occupy and radius), and uncover the universal characteristics for these new nanostructured systems. We will focus on magnetic anisotropy, magnetic flip, magnetic transition temperature, and so on. And we will use Monte Carlo approach with the scaling method to establish appropriate theoretical models and determine the scaling exponents. The research project has important significance to comprehend the physical mechanism of the size effect on the magnetic transition temperature of novel nanostructured magnetic materials, and enrich methods and theories of the magnetic micro and nanostructure devices.

英文关键词： Nanostructre;Magnetic transition temperature;Anisotropy;Ferrite;Size effect