The effect of rare-earth oxide CeO2 on the electromagnetic properties of ferrite-ceramic composite materials
In this work, we present the influence of rare-earth element additions on this new composite material. A great improvement of the electromagnetic properties was obtained. The constituent chemicals were mixed in the stoichiometric composition, calcined at 850degC for 2 h and blended with PVA to press into steroidal or disc shaped specimens. These specimens were sintered at 900degC for 2.5 h in air. The complex permeability, capacity and impedance were measured with HP4291B and 4291A instruments, respectively, in the frequency range from 1MHz to 2GHz.
Synthesis and electromagnetic properties of ferroelectric-ferromagnetic composite material
Abstract Ferroelectric–ferromagnetic composite materials which possess both capacitive and inductive properties for suppressing electromagnetic interference (EMI) were synthesized by usual ceramic technology. These composite materials have relatively high dielectric constant ( e r = 70 ) and high relaxation frequency (fr>1.8 GHz). The influences of different composition on the electromagnetic properties of composite materials were investigated. The microstructures of the sintered ceramics were observed and analyzed by SEM. It was found that the average grain size of sintered ceramics was smaller than 5 μm and the densities ranged from 4.9 to 5.3 g/cm3.
Piezoelectric and Magnetoelectric Properties of Lead Zirconate Titanate/Ni-Ferrite Particulate Composites
Piezoelectric and magnetoelectric properties of magnetoelectric particulate composites with Lead Zirconate Titanate (PZT) and Ni-ferrite were investigated. The maximum magnetoelectric voltage coefficient, (dE/dH)max, increased with higher sintering temperature up to 1250°C. Composites sintered at 1300°C, had dissolution of Fe ions into PZT, or interdiffusion between PZT and ferrite. Connectivity of the ferrite particles and sintering temperature were important factors for fabrication of this particulate composite. The composite added with 20 wt.% amount of Ni-ferrite, sintered at 1250°C for 2 hours, had the highest magnetoelectric voltage coefficient of 115 mV/cm · Oe at room temperature. This value is comparable to that of the BaTiO3-CoFe2O4 based composites reported by Philips laboratory, and is 44% higher than other magnetoelectric particulate composites.