Effect of the piezomagnetic NiFe2O4 phase on the piezoelectric Pb(Mg1/3Nb2/3)(0.67)Ti0.33O3 phase in magnetoelectric composites

The magnetoelectric (ME) effect in magnetoelectric composites is an induced electric polarization in response to an applied magnetic field and magnetization in response to an applied electric field. The individual phases NiFe2O4 (NFO), Pb(Mg1/3Nb2/3)(0.67)Ti0.33O3 (PMN-PT) and composites of (x) NFO + (1 - x) PMN-PT with x = 0.15, 0.30 and 0.45 were prepared using a solid-state reaction technique. The presence of NFO and PMN-PT was confirmed using x-ray diffraction. Scanning electron microscopy (SEM) images were used to study the microstructure of the composites. The connectivity scheme present in the ME composites was investigated from the microscope images. The connectivity scheme changes with change in the NFO content in the composites. A ferroelectric hysteresis loop (at 50 Hz) was obtained and studied at room temperature. Variation of the dielectric constant with temperature for all the composites was studied in the range 300-925 K. Here we report the effect of NFO mole fraction on connectivity schemes between NFO and PMN-PT grains, % porosity, magnetoelectric and magneto-dielectric effects in NFO/PMN-PT composites. The maximum value of the magnetoelectric voltage coefficient, 10.43 mV cm(-1) Oe(-1), was obtained for 0.15 NFO + 0.85 PMN-PT composites. The maximum value of the magneto-dielectric coefficient, 4.54, was obtained for 0.15 NFO + 0.85 PMN-PT composites.