Structural analysis and electrical properties of ME composites

Abstract

The magnetoelectric (ME) composites are obtained by binding a magnetostrictive phase with piezoelectric phase so as to obtain the magnetoelectric output. The magnetoelectric composites with a general formula ( x) BaTiO 3 + (1 − x) Ni 0.92Co 0.03Mn 0.05Fe 2O 4 in which x varies as 0.85, 0.70 and 0.55 were prepared by standard double sintering ceramic method. The structural analysis was carried out to confirm the presence of two phases in composites. The dc resistivity ( ρ dc) was measured as a function of temperature in the range 300–800 K. The variation of resistivity with temperature shows semiconducting behaviour. The variation of dielectric constant and dielectric loss in the frequency range 100 Hz–1 MHz was studied. The conduction is explained on the basis of small polaron model. The confirmation of this phenomenon was made with the help of ac conductivity measurements. The hysteresis measurements were carried out to determine saturation magnetization (Ms) and coercivity (Hc). The variation of saturation magnetization and magnetic moment ( μ B) is interpreted in terms of composition. The static magnetoelectric conversion factor (d E/d H) was measured as a function of dc magnetic field. The maximum value of d E/d H was found to be 354 μV/cm. Oe for a composite with x = 0.85.