Magnetoelectric effect and electrical properties in BTO + Ni0.93Co0.02Cu0.05Fe2O4 particulate composites

Two phase particulate magnetoelectric (ME) composites with compositions (1 - y)BaTiO3 (BTO) + (y)Ni0.93Co0.02Cu0.05Fe2O4 (NiCoCu) (where y = 0.00, 0.15, 0.30, 0.45 and 1.00) were prepared by double sintering ceramic technique. X-ray diffraction patterns confirm the presence of the constituent phases, i.e. ferroelectric and ferrite phase in the composites. Studies on dc resistivity and thermo-emf as a function of temperature were carried out. ac conductivity measurements in the frequency range 100 Hz to 1 MHz, conclude that the conduction is due to small polaron hopping mechanism. The variation of dielectric constant and loss tangent (tan δ) in the frequency range 20 Hz to 1 MHz was also studied. The magnetoelectric voltage coefficient (dE/dH)H was measured as a function of intensity of applied magnetic field and mole percent of constituent phases at room temperature. The maximum magnetoelectric voltage coefficient of 587.75 μV/cmOe was observed for 70% BaTiO3 + 30% Ni0.93Co0.02Cu0.05Fe2O4 composite at dc magnetic field of 2.1 kOe. The ME response has been explained in terms of resistivity and content of ferroelectric phase