摘要
在强磁场下采用共沉淀-相转化法制备出了纳米级的钴铁氧体颗粒;通过SEM,XRD和VSM等分析手段,考察了磁感应强度对纳米钴铁氧体形貌及性能的影响规律．结果表明:无磁场及磁感应强度小于2 T时,纳米钴铁氧体颗粒为球形;当磁感应强度大于、等于4 T时,棒状纳米钴铁氧体开始形成．随着磁感应强度的增大,棒状纳米颗粒数量增加,纳米钴铁氧体的晶化程度提高,磁性能(Mr,Ms,Mr／Ms)也大幅度提高。与无磁场相比, 10 T时制备的纳米钴铁氧体颗粒的剩余磁化强度Mr增加近15倍,饱和磁化强度Ms提高约1．44倍．从磁聚合定向生长和临界磁畴角度分析了强磁场影响共沉淀-相转化法制备的纳米钴铁氧体的形貌、晶化程度及磁性变化的机理．
Cobalt ferrite nanoparticles were synthesized in high static magnetic field by coprecipitation-phase transformation way, and the influences of magnetic flux density （MFD） on the shape and properties of the nanoparticles are studied through SEM, XRD and VSM. It was shown that when there was no magnetic field or MFD was lower than 2 T the spheric nanoparticles are obtained, and when MFD was equal to or above 4 T the nanorods appear. With the increase of MFD, much nanorods were obtained, and the crystallinity of cobalt ferrite became better, also the magnetic properties such as remanence magnetism （Mr）, saturation magnetism （Ms） and squareness ratio （Mr/Ms） were increased remarkably. The Mr value of cobalt ferrite prepared in 10 T magnetic field was 15 times to that without magnetic field, and the Ms was elevated by 1.44 times. Based on the theory of magnetic aggregation and critical magnetic domain, the mechanism of how the high static magnetic field affected the shape, crystallinity degree and magnetic properties of the prepared cobalt ferrite was discussed.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第5期529-533,共5页
Acta Metallurgica Sinica
基金
国家自然科学基金项目50404018
全国优秀博士学位论文作者基金项目200235
上海市科委纳米专项基金项目0252nm048资助
关键词
钴铁氧体
纳米
强磁场
共沉淀
cobalt ferrite, nanorode, high static magnetic field, coprecipitation
