Dielectric Tunability in Ferromagnetic-Ferroelectric Composite System

Abstract

A new kind of lead-free ferromagnetic-ferroelectric (FM/FE) composite was successfully prepared by incorporating the dispersed 0.15Ni0.98Co0.02Fe2O4 (NCF) ferromagnetic nanoparticles into 0.85(K0.5Na0.5)NbO3-LiSbO3 (KNN-LS) ferroelectric micromatrix. The relative dielectric constant (εr) of the ceramic as a function of frequency (0.1 -200 kHz) under different dc bias electric field strengths was investigated in detail. εr increases with increasing dc bias electric field, while tanδ decreases with the increase in frequency. At room temperature, the high dielectric tunability (KD=11.41%) and high figure of merit (FOM=15.66) under the low dc electric field of 3 kV/cm, clearly imply that these ceramics are promising materials for tunable microwave device applications.