织构化稀土取代铁氧体制备与磁性、磁光、毫米波特性的研究

Up till now, there still exist some key scientific problems for traditional materials in the different application such as permanent magnetic properties, magneto-optical activity and microwave/millimeter wave characteristics. We have given undivided attentions to its composition, structure, grain growth, the orientation of magnetic moment distribution and arrangement, single domain structure of the effective control by the mothod of mulit-ionic substitution and an applied magnetic field as a degree of freedom to induce an orientational ordering in order to synthesize the new unexpected materials or abtain an expected structure..By preparing a permanent magnetic material under an applied magnetic field and then manufacturing highly textured permanent magnet under temperature gradient technique and an applied field with a substitution of rare earth ions, this research explore an inner link of microstructure and physical properties. Firstly, by adjusting the crystallographical site occupied by rare earth ions, it is hoped that the materials with high saturation and permanent magnets with a higher intrinsic coercivity and a larger remanence will be discovered. Secondly, with the effect of 4f electron on the sensitization and quenching of a light and preparetion by highly textured permanent magnets, we will discover the coupling mechanism of a magnetic moment and the radial and poloidal magneto-optical activity. Thirdly, ferrite magnets, which are pressed under an applied field, some temperature gradient and stress, will carry out the shift of resonant frequency from 20Ghz to 50GHz and a low magnetic loss with a FMR derivative linewidth in order to provide the necessary biasing magnetic ?eld for a transceiver operation..To sum up the points which we have just indicated, this project aims to research into highly textured permanent magnetic magnets with a substitution of rare earth ions for magnetic properties, magneto-optical activity and millimeter wave characteristics, in which it not only has rich content of academic research, also has important practical value. Thus, it is expected to achieve a number of innovative research results.

通过组合离子取代、添加外加磁场自由度，对永磁材料在组成、结构、晶粒进行优化，以期对磁矩的取向与排布、单畴结构等进行有效的人为控制，从而设计出特殊物性的材料，依然存在一些关键的科学问题。本研究通过稀土离子取代次晶位，在外加磁场下制备铁氧体材料，在一定温度梯度和外加磁场下制备织构化的永磁体，探索材料微结构与物性的内在本质。首先，通过调控材料的高饱和磁化强度，制备出具有高剩磁和高内禀矫顽力的永磁体。在此基础上，对永磁体进行织构化制备，探索 4f电子对光的敏化和猝灭机制，发现磁矩取向与纵向和极向磁光的耦合效应。通过磁场、温度梯度和应力调控，在满足ΔH前提下，为铁氧体微波收发器提供需要偏置场，降低损耗，实现共振频率从20GHz到50GHz位移。因此，本课题提出织构化稀土取代永磁体制备与磁性、磁光、毫米波特性的研究，不仅具有丰富的物理研究内涵，还拥有重要的应用价值，有望取得一些创新性的研究成果。

本课题联合运用多种科研手段，研究了织构化永磁铁氧磁体。首先，以多种离子联合取代取代次晶位，在外加磁场下制备铁氧体材料，在一定温度梯度和外加磁场下制备织构化的永磁体，探索材料微结构与物性的内在规律。其次，通过研究确定的六角晶体结构的铁氧体R1-x-yCaxLayO • nFe2-zCoz/nO3，调控材料的高饱和磁化强度，制备出具有高剩磁和高内禀矫顽力的永磁体。在此基础上，探索了 4f电子对光的敏化和猝灭机制，发现了磁矩取向与纵向和极向磁光的耦合效应有趣的结果。研究结果表明，钴取代可显著影响六角锶铁氧体磁性能，钴取代铁可以明显地增强六角锶铁氧体的磁光克尔效应。对于R1-x-yCaxLayO • nFe2-zCoz/nO3体系中的Sr0.70-xLa0.3CaxFe11.7Co0.3O19，磁光克尔效应可以增加到0.4%。本课题提出织构化稀土取代永磁体制备与磁性、磁光等特性的研究，不仅具有丰富的物理研究内涵，还拥有重要的应用价值，已取得了一些创新性的研究成果。.本研究部分成果支持了产品的产业化，获安徽省科技进步二等奖一项。发表SCI、EI论文篇39篇，国内会议报告6次，国际学术交流1次，授权专利2项，已毕业硕士生10名，博士2名。