Electrical conduction and magnetoelectric effect in CuFe1.8Cr0.2O4-Ba0.8Pb0.2TiO3 composites

Magnetoelectric composites of CuFe1.8Cr0.2O4-Ba0.8Pb0.2TiO3 were prepared u sing high temperature solid-state reaction technique. X-ray structural anal ysis of these composites confirms the presence of both the phases in the co mposite. Detailed studies of dielectric properties (epsilon', tan delta and sigma (ac)) as a function of frequency (100 Hz to 1 MHz) and temperature ( 30 degreesC to 250 degreesC) show that these compounds exhibit diffuse ferr oelectric phase transitions. Results of ac conductivity, dc resistivity and thermoelectric power measurements show that conduction occurs by hopping o f charge carriers. The magnetoelectric effect has been studied as a functio n of intensity of magnetic field. The electrical polarisation was induced i n piezoelectric (Ba0.8Pb0.2TiO3) phase as result of strain induced in the f errite (CuFe1.8Cr0.2O4) phase by the applied magnetic field. The Jahn-Telle r distortion caused in the ferrite lattice by Jahn-Teller ions like Cu2+ an d Cr3+ is also responsible for the elastic coupling of strain to the Ba0.8P b0.2TiO3 phase.