Synthesis and electrical properties of 1-x(Na0.5K0.5NbO3)-x(CoFe2O4)

Magnetoelectric (ME) effect is a coupled two-field effect in which application of an electric field induces magnetization and a magnetic field induces electrical polarization. Na1-xKxNbO3 (NKN) is a combination of ferroelectric KNbO3 and antiferroelectric NaNbO3, and forms a morphotropic phase boundary (MPB) near 50/50 composition (x=0.50) separating two orthorhombic phases. CoFe2O4 (CFO), on the other hand, is well known spinel ferrite with high Curie temperature. We have synthesized ceramic composites,1-x(Na0.5K0.5NbO3)-x(CoFe2O4) with x = 0.0 to 1.0 (in step of 0.2) by standard solid state reaction route. Powder XRD show a mixed cubic phase without impurity peaks for the samples under study. In low frequency range the dielectric properties of the NKN/CFO composites show Maxwell-Wagner relaxation. Systematic change in the electrical polarization with increasing x was observed at various applied fields at room temperature.