Magnetoelectric coupling in ε-Fe2O3 nanoparticles

Nanoparticles of the ferrimagnetic ε-Fe 2 O 3 oxide have been synthesized by the sol–gel method. Here we report on the measurement of the dielectric permittivity as a function of temperature, frequency and magnetic field. It is found that, coinciding with the transition from collinear ferrimagnetic ordering to an incommensurate magnetic state occurring at about 100 K, there is an abrupt change (about 30%) of permittivity, suggesting the existence of magnetoelectric coupling in this material. Indeed, magnetic field-dependent measurements at 100 K have revealed an increase in the permittivity of about 0.3% in 6 T. Possible advantages of ε-Fe 2 O 3 as a magnetoelectric material are discussed.