To determine the activation energies of magnetoelectric interaction in the BiFeO3/PbTiO3 superlattice, the ferroelectric and magnetic hysteresis loops and the temperature dependences of the permittivity and magnetic permeability of BiFeO3 and PbTiO3 have been analyzed. The activation energies of the irreversible motion of ferroelectric and magnetic domain walls in electric (4.3–6.6 meV for BiFeO3; 0.3–1.7 meV for PbTiO3) and magnetic (0.3–4.8 meV for BiFeO3) fields are determined for the first time. The activation energies of the permittivity (0.43 eV) and magnetic permeability (0.85 eV) have been determined for different temperatures in the vicinity of the Curie and Néel points, respectively. It is shown that in the BiFeO3/PbTiO3 superlattice the activation energy of magnetoelectric coupling has a linear dependence on the interface thickness at different temperatures. From this, a conclusion is made about the presence of an activation mechanism of magnetoelectric interaction in the superlattice. For the first time, a linear dependence on temperature of the ratio of the activation energies of permittivity and magnetic permeability is obtained, which is proportional to the magnitude of the magnetoelectric effect, which, in turn, is inversely proportional to the interface thickness. The presence of a mechanism of strong magnetoelectric interaction in the BiFeO3/PbTiO3 superlattice is shown.
Kuzenko et al. (Mon,) studied this question.