A magnetoelectric multiferroic nanocomposite. The nanocomposite comprises a ferroelectric perovskite oxide and a rare-earth substituted mixed ternary transition metal ferrite of the formula A1−xBxRyFe2−yO4. The nanocomposite has a high dielectric constant, low dielectric loss, both stable over a wide frequency range. These properties may make the nanocomposite desirable for applications in microelectronic devices, sensors and antennas.