Conductivity, dielectric behaviour and magnetoelectric effect in copper ferrite-barium titanate composites

Composites of CuFe2O4 and BaTiO3 were prepared using a conventional ceramic double sintering process. The presence of both phases was confirmed by X-ray diffraction. The variations of resistivity and thermo emf with temperature in these samples were studied. All the composites showed n-type behaviour. The variation of dielectric constant (epsilon') in the frequency range 100 Hz to 1 MHz and with temperature at constant frequency were studied. The conduction phenomenon was explained on the basis of a small polaron-hopping model. Also confirmation of this phenomenon was made with the help of a.c. conductivity measurements. The static value of the magnetoelectric conversion factor, i.e. d.c. (ME)(H) was studied as a function of intensity of the magnetic field. The maximum value of ME coefficient was observed for 75% ferroelectric phase composite.