Structural analysis, magnetic properties and magnetoelectric effect in piezomagnetic–piezoelectric composites

The ferrite–ferroelectric composites of Ba0.8Pb0.2TiO3 phase combined with different ferrite phases like CuFe2O4, CuFe2−xCrxO4, and MnFe2−xCrxO4 (x indicates the molar fraction of the substituent's in the ferrite phase and varies as 0.2 and 0.4) were prepared by standard ceramic technique. The magnetoelectric (ME) effect in such composites is due to the strain induced in the ferrite phase by an applied magnetic field, which in turn gives rise to an electric voltage in the ferroelectric phase as a result of piezoelectric effect. The constituent phase, namely the ferrite phase being a driving force in the observation of ME effect, the effect of its variation is considered in the present communication. Structural characterization reveals that CuFe2O4 results in large distortion as compared to the other ferrites. The magnetic properties like ac susceptibility and hysteresis measurements reveal the existence of single domain particles in the composites of CuFe2O4 and Cu–Cr ferrites where as multidomain particles in the composites of Mn–Cr ferrites. The large value of magnetoelectric conversion factor (a measure of ME effect) is observed in the composites containing CuFe2O4. From this study it is concluded that the single domain particles of the ferrite phase together with large lattice distortion serve as better candidates in piezomagnetic effect and hence enhance the ME output.