摘要
制备了MnZn铁氧体 SiO2 颗粒复合体 .研究了磁性颗粒复合体的有效磁导率 μ、比磁化强度σ以及矫顽力Hc随磁性颗粒含量的变化 .研究发现 ,在MnZn铁氧体体积百分含量为 90 %— 98%的区域 ,复合体的有效磁导率 μ的变化速率发生突变 ,出现磁渗流现象 ,从实验得到的体系磁渗流阈值Vc=97 9% .在磁渗流区 ,矫顽力表现出异常行为 .结果表明 ,这种异常行为与复合体微观结构有着密切关系 .在磁渗流前 ,矫顽力Hc 的变化主要来源于磁性颗粒间磁偶极子的相互作用 ;而在磁渗流后 ,颗粒复合体比磁化强度σ的增大是决定矫顽力呈下降趋势的主要因素 .
MnZn-ferrite/SiO2 particle composites are prepared by mechanical balling. We study the relations of effective permeability mu, specific magnetization sigma and coercivity H-c with the MnZn-ferrite concentration. The results indicate that an abrupt change emerges in effective permeability when the volume percentage of MnZn-ferrite particles is near V = 98%, which means that a magnetic percolation phenomenon occurs in the system. Meanwhile, it is found that the coercivity H-c exhibits an anomalous behaviour that depends strongly on the microstructure of the composite. Above the percolation threshold, the variation of coercivity can be mostly explained in terms of dipolar interaction between magnetic particles, whereas below the percolation threshold, the decrement of H-c is ascribed dominantly to increasing specific magnetization a. At the same time, we determine the measured percolation threshold V-c = 97.9%, which can be derived from the maximum of d(2)mu/dV(2).
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2003年第8期2052-2056,共5页
Acta Physica Sinica
基金
江苏省教育委员会自然科学研究基金 (批准号 :Q110 890 7)资助的课题 .~~
