Complex magnetoelectric effect in multiferroic composites: the case of PFN-PT/(Co,Ni)Fe₂O₄

Abstract

We report a systematic study of the magnetoelectric (ME) voltage coefficient as a complex quantity in the particulate composite of ferroelectric solid solution 0.94Pb(Fe1/2Nb1/2)O3-0.06PbTiO3(PFN-PT) with CoFe2O4(CFO) and NiFe2O4(NFO) ferrites. The results show that the real part of the ME voltage coefficient () is highly influenced by the magnetostrictive phase through . NFO produces larger at a lower magnetic field, which originates from the softer magnetic properties. In addition, was found to be positive for NFO composite, while CFO composite shows a negative ME voltage coefficient at high magnetic fields. We argue that the field dependence of can be interpreted using the dynamic piezomagnetic coefficient, . The imaginary part of the ME voltage coefficient () was also determined for all composites. Both the and show a peak at the same magnetic field, which is attributed to the maximum dynamic piezomagnetism when the magnetic domains are collectively rotated by the dc bias magnetic field. Our results show that the ME voltage coefficient in the composites of PFN-PT/(Co,Ni)Fe2O4 is highly influenced by the content, magnetic softness and field dependence behaviour of magnetostriction of the piezomagnetic phase.