Investigations on Magnetoelectric and Magnetodielectric Properties of CMFO-PBT Composites

摘要

The present paper reports the dielectric, magnetodielectric, and magneto-electric properties of Mn-substituted Co_(1.2-x)Mn_xFe_(1.8)O_4 (CMFO) and Pb_(0.2)Ba_(0.8)TiO_3 (PBT) magnetoelectric (ME) composites. The Co_(1.2-x)Mn_(x)-Fe_(1.8)O_4 is initially studied for variation of electrical resistivity ρ, saturation magnetization M_s, permeability μ, coercive field H_c, and coefficient of magnetostriction λ to determine compositions suitable to form the ME composite. Here, x = 0.4 and 0.1 are observed to possess optimum values of ρ, M_s, μ, H_c, and λ; therefore, the composites are formed using Co_(0.8)Mn_(0.4)Fe_(1.8)O_4 (CMFO 0.4) as well as Co_(1.1)Mn_(0.1)Fe_(1.8)O_4 (CMFO 0.1). The composites were synthesized and investigated for their structural, dielectric, magnetoelectric, and magnetodielectric properties. The dielectric constant of the composites is observed to exhibit a contribution due to interfacial polarization as well as a contribution due to the PBT phase. The variation of the linear magnetoelectric coefficient, α, quadratic magnetoelectric coefficient, β, and magnetocapacitance, M_c, for various compositions are reported in this paper. The paper also reports the effect of sintering temperature and variation of frequency on the magnitude of α and M_c. The samples with y = 0.5 are observed to show a sufficiently large and useful magnitude of magnetoelectric coefficients and M_c value.