Dy_(2)O_(3)掺杂对MnZn铁氧体的结构及高频电磁特性的影响

Effect of Dy_(2)O_(3) doping on the microstructure and high frequency electromagnetic properties of MnZn ferrite

采用固相反应法制备了Dy_(2)O_(3)掺杂MnZn铁氧体,分别采用X射线衍射仪(XRD)、扫描电镜(SEM)、振动样品磁强计(VSM)、LCR表以及B-H仪等对样品的结构和电磁性能进行表征。结果表明,在Dy_(2)O_(3)掺杂量为0~0.1 wt%,样品均为单相立方尖晶石结构;当Dy_(2)O_(3)掺杂量为0.05 wt%,样品呈现出较大的晶粒尺寸和密度,此时,具有最大的饱和磁化强度95.8 A·m^(2)/kg和最小的矫顽力55.9 A/m;起始磁导率提高至845,相对于未掺杂样品增幅为32%,在1 MHz、50 mT、25℃的测试条件下,损耗降低幅度为20%;此外,利用等效电路模型对不同Dy_(2)O_(3)掺杂量样品进行了晶粒电阻和晶界电阻分离,并初步分析了Dy元素影响MnZn铁氧体涡流损耗的机制。

Dy_(2)O_(3)-doped MnZn ferrites were prepared by solid-state reaction method.The structure and electromagnetic properties of the samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),vibrating sample magnetometer(VSM),LCR and B-H instrument,respectively.The results indicate that the samples show a single-phase cubic spinel structure for Dy_(2)O_(3)content 0-0.1 wt%.It is seen that the samples with 0.05 wt%dosage of Dy_(2)O_(3)exhibit relativley large grain size and density.Meanwhile,the maximum saturation magnetization of 95.8 A·m2/kg and the minimum coercivity of 55.9 A/m are obtained.More importantly,the initial permeability of the sample increases to 845,which is 32%higher than that of undoped sample.In addition,the core loss decreases by 20%under test conditions of 1 MHz,50 mT and 25℃.Furthermore,for the samples with different Dy_(2)O_(3)content,the resistance separation of grain and grain boundary is conducted according to equivalent circuit model.Then the mechanism of Dy element affecting the eddy current loss in MnZn ferrite is discussed preliminarily.