采用固相反应法制备Ni0.5Zn0.5Nd x Fe2-x O4铁氧体,通过X射线衍射仪(XRD)、阻抗分析仪和振动样品磁强计(VSM)对样品的物相、结构和电磁性能进行表征,讨论了Ni0.5Zn0.5Nd x Fe2-x O4(x=0.002~0.010)铁氧体的结构和电磁性能。结果表明:Nd3+掺杂量x>0.008时,样品中出现了杂相NdFeO3;随着Nd3+掺杂量的增加,晶格常数呈现先增大后不变,而密度、介电常数和介电损耗角正切呈现先增大后减小(x=0.008时出现最大值),但饱和磁化强度呈现逐渐减小(x=0.010时有最小值71.22 emu/g);并且所有样品的介电损耗角正切均出现峰值,表现异常的介电行为。
A series of Cu-substituted Ni_(0.5-x)Cu_xZn_(0.5)Fe_2O_4(x=0.12,0.16,0.20,0.24 and 0.28) spinel ferrites were prepared by conventional ceramic method to investigate the effects of Cu compositional variation on the structure and dielectric properties.XRD patterns demonstrate that all the samples are crystallized in single-phase cubic spinel structure and the lattice constant increases with increasing Cu content.White grains observed by SEM are Cu-rich phase.The dielectric constant versus frequency curve displays a normal dielectric behavior of spinel ferrites.While the frequency dependence of dielectric loss tangent is found to be abnormal,exhibiting a peak at certain frequency for all Cu-substituted Ni-Zn ferrites.A maximum of the resistivity is observed at x=0.2 due to the decrease of hopping electrons between Fe^(2+) and Fe^(3+) in per unit volume,which is in contrast with the Cu content dependence of dielectric constant and dielectric loss.