【摘要】 采用溶胶-凝胶法制备了0.15CoAl0.2Fe1.8O4-0.75BaTiO3纳米磁电复合材料。XRD分析表明,制备的样品中包含钙钛矿(BaTiO3相)和尖晶石结构(CoAl0.2Fe1.8O4相),没有其它明显杂相生成。扫描电镜表明,颗粒平均粒径约为45nm,且压磁相均匀分布于压电相中。研究了该纳米磁电复合材料在外加偏置静电场诱导下的介电常数随频率的变化,分析了直流偏置电场诱导下的相对介电常数变化值Δεr和调谐率K。随着偏置电场的增大,Δεr和K都变大;随着频率的增加,Δεr和K都减小。并且,在外加偏置电压为3kV/cm时可以获得相对较大的调谐率(4.05%)。更多还原

【Abstract】 Magnetoelectric nano-composites of 0.15CoAl0.2Fe1.8O4-0.75BaTiO3 are synthesized by sol-gel method. The XRD reveals that both the parent phases of perovskite BaTiO3 and spinel CoAl0.2Fe1.8O4 are present with no sign of undesired phases in the sample. The SEM images show that nano-particle crystallite size is about 45nm.The relative dielectric constant as a function of frequency under applied electric fields is characterized. The electric-field-induced variation of dielectric constant Δεr and the tunability are also investigated. The value of Δεr and K raises with the increase in DC bias field and decreases with the increase in frequency. The K value is as larger as 4.05% under the low DC electric field of 3kV/cm.更多还原