Magnetoelectric coupling susceptibility from magnetodielectric effect

A multiferroic material with a pronounced degree of the magnetoelectric (ME) coupling at room temperature is of great technological importance. A widely used method of indirectly assessing the ME coupling is based on the magnetodielectric (MD) effect, which accounts for the variation in dielectric permittivity under an applied bias magnetic field. At the present stage, however, there is no systematic guideline on evaluating the ME coupling susceptibility from the MD effect. Here we propose a simple theoretical method of estimating the ME coupling susceptibility using the MD data. This alternative approach is applied to an epitaxially grown La-doped BiFeO3 thin film as an illustrative example.