Structural and electro-magnetic properties of low temperature co-fired BaSrTiO3 and NiCuZn ferrite composites for EMI filter applications

Abstract

For the application of electro-magnetic interference filter, magneto-electric composites of spinel ferrite (Ni0.25Cu0.20Zn0.55)Fe2O4 and dielectric (Ba0.75Sr0.25)TiO3 have been prepared by a standard ceramic technique and the effects on structural, dielectric and electro-magnetic properties have been investigated. Ferrite-dielectric mixed powder is uniaxially pressed into toroids and pellets. Specimens are sintered at 950 °C. Powder X-ray diffraction (XRD) indicates a mixed phase of composites with spinel and perovskite phase. The microstructural analysis shows dense structure with some porosity. The variations in dielectric constant and loss tangent with frequency are also studied. The dielectric constant of composite continuously decreases and permeability increases with increasing ferrite content. Observations of P–E hysteresis loops and M–H hysteresis loops, respectively, confirm the dielectric and ferromagnetic nature of the composite samples. © 2017, Springer Science+Business Media, LLC.