Dielectric and magnetoelectric behavior of NixCu1-xFe2O4-PbZr0.52Ti0.48O3 laminated multilayered nanocomposites

Magnetoelectric nanocomposites NixCu1-xFe2O4-PbZr0.52Ti0.48O3 (where x = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.9) are synthesized by solution autocombustion method. The XRD study reveals the formation of spinel structure in ferrite phase and perovskite structure in ferroelectric phase. Multilayers of these two phases (ferrite/PZT/ferrite) are fabricated using screen printing technique on fluorine-doped tin oxide (FTO)-coated glass substrates. The dielectric properties are measured in the frequency range 100 Hz to 1 MHz at room temperature as well as at elevated temperatures. The dielectric constant decreases with increase in frequency exhibiting the normal dielectric behavior. The frequency vs. loss tangent plot reveals the presence of absorption peaks in all the samples in the frequency range studied, indicating the presence of resonance phenomenon. The AC resistivity decreases with rise in frequency and remains constant at higher frequency. The decrease in AC resistivity with increase in frequency is attributed to the increase in the hopping frequency of small polarons between the equivalent ionic sites. The magnetoelectric (ME) voltage coefficient was measured with respect to the applied DC bias magnetic field for the trilayered structures. As the applied DC magnetic field increases, the transverse ME voltage coefficient (alpha(E31)) gradually increases and reaches a peak value at the applied magnetic field of 400 Oe and then decreases beyond this field. It is also found that the composition parameter 'x' of the ferrite phase has not influenced much the ME effect. Ni-rich samples have showed better ME effect than Cu-rich samples, which could be attributed to the reduction in Jahn-Teller distortion effect. The value of ME voltage coefficient reaches a saturation beyond 600 Oe.