Multiferroics are a In this thesis, solid solution of lead-iron niobate and lead titanate (Pb(Fe 0.5 Nb 0.5 )O 3 -PbTiO 3 ) as ferroelectric phase and Zn-substituted cobalt ferrite as magnetic phase were used. Composite samples of Pb(Fe 0.5 Nb 0.5 )O 3 -PbTiO 3 /CoFe 2-x Zn x O 4 (x=0, 0,025, 0.1, 0.2, 0.3) containing 60 Wt\\% ferroelectric and 40 Wt\\% ferrite were prepared. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) were done on all of the samples. Dielectric constant and ferroelectric hysteresis loop were measured for all of the samples. Magnetic hysteresis loop was measured by a vibrating sample magnetometer (VSM). ME coupling coefficient was measured for all of the composite samples by lock-in amplifier technique. Highest ME coefficient value of 12.33 was obtained for x=0.1 at the magnetic field of 755 Oe. Results revealed that the magnetic field at which the maximum value of ME coefficient was observed (H peak ), strongly depends on the value of Zn substitution. The results were interpreted using the magnetic field dependence of magnetostriction.
