Dielectric and magnetic properties of three-layers laminated ceramic composite, K0.5Na0.5NbO3/CoFe2O4/K0.5Na0.5NbO3

Abstract

Three-layers laminated ceramic composite system of K0.5Na0.5NbO3/CoFe2O4/K0.5Na0.5NbO3 (KCK) were prepared by conventional solid state reaction method. SEM analyzes revealed negligible inter-diffusion of chemical elements along the boundary layers in the laminated ceramic composite, KCK. The relative dielectric permittivity of the sandwiched ceramic composite was investigated in a broad frequency range, 101 –106 Hz at room temperature. The real part of the relative dielectric permittivity of KCK was strongly frequency dependent; being ∼ 1250 and ∼ 700 for 100 and 1 KHz, respectively. Also the dielectric study showed a deviation of Cole–Cole relaxation in CoFe2O4 and KNa0.5NbO3 materials to Maxwell–Wagner relaxation in the KCK. It was found that the magnetic properties such as saturation magnetization (Ms ∼ 77 emu/g), remanent magnetization (Mr ∼ 12 emu/g) and coercive field (Hc ∼ 320 Oe ) of KCK were quite the same as ferrimagmetic spinel bulk cobalt ferrite at room temperatur