The multiferroism is characterized by the existence of two or more ferroic orders in matter. Magnetoelectric (ME) materials are the combination of ferromagnetic and ferroelectric orders that present a coupling between the magnetic and electric fields. This property allows to control the magnetic response due to an applied electric field and vice versa. An alternative to obtain multiferroic materials is the production of composite that combine ferroelectric and magnetic materials. The use of magnetostrictive materials as ferromagnetic phase in composites is very important because the mechanical stress applied in ferroelectric phase induces the appearance of magnetoelectric effect. Our group has been study multiferroic composite materials with goal to understand magnetostriction and magnetoelectric effects via magnetization and AC susceptibility measurements using a phenomenological approach. We show that the magnetostrictive behavior of these materials is influenced by the piezomagnetic response and the stress of the piezoelectric matrix [1]. The magnetoelectric response of composites, at low temperatures, can be understood proposing that the ferromagnetic and ferroelectric phases are coupled by the interaction of the spins of the ferromagnetic phase with the composite phonons through spin/lattice relaxation. This assumption expands understanding of ME effect response on dynamic magnetization, based on the magnetic relaxation [2]. These models were applied with successful for (1-x)Pb(Mg1/3Nb2/3)-xPbTiO3/CoFe2O4 (PMN-PT/CoFe2O4) of the 0-3 type magnetoelectric particulate biphasic.
References
[1] A. J. Gualdi et al., J. Appl. Phys. 114, 053913 (2013).
[2] A.J. Gualdi et al., J. Appl. Phys. 119, 124110 (2016).