Electrical properties and magnetoelectric effect in Ni 0.75Co 0.25Fe 2O 4+Ba 0.8Pb 0.2TiO 3 composites

Abstract

Magnetoelectric (ME) phenomenon has been observed in several single phase materials in which simultaneous electric and magnetic ordering co-exists and in two-phase composites in which the participating phases are ferrite and ferroelectric. Hence, ME composites with composition xBa 0.8Pb 0.2TiO 3+(1− x)Ni 0.75Co 0.25Fe 2O 4 in which x varies as 0.0, 0.55, 0.70, 0.85 and 1.0 were prepared by ceramic method. The presence of both phases was confirmed by x-ray diffraction technique. The variation of resistivity and thermoemf of the composites with temperature was studied. The variation of dielectric constant ( ε′) with frequency (100 Hz to 1 MHz) and with temperature at different frequencies viz. 1, 10, 100 kHz and 1 MHz has been also studied. The AC conductivity is derived from dielectric constant ( ε′) and loss tangent (tan δ). The nature of conduction has been discussed with the help of polaron hopping model. The static value of the ME conversion factor i.e. DC (ME) H was studied as a function of intensity of the magnetic field. The maximum value of DC (ME) H was found to be 140 μV cm −1 Oe −1.