Phosphate bonded CoFe2O4–BaTiO3 layered structures: Dielectric relaxations and magnetoelectric coupling

Abstract

Multilayered phosphate bonded CoFe2O4–BaTiO3–CoFe2O4 (CBC) and BaTiO3–CoFe2O4–BaTiO3 (BCB) multiferroic structures were formed by means of uniaxial pressing. The dielectric properties were studied in 20 Hz – 1 GHz frequency and 120–500 K temperature ranges. The complex dielectric permittivity is 15–0.17i for CBC and 22–0.04i for BCB, it is temperature- and frequency-independent below 250 K. At higher temperatures, strong dispersion appeared governed by the Maxwell–Wagner relaxation. Such behaviour is determined by the 2–2 connectivity of the sample. The highest direct magnetoelectric coupling coefficient was found for the BaTiO3–CoFe2O4–BaTiO3 structure of 0.2 mVOe–1cm–1.