Percolative dielectric behavior of wet chemical synthesized lead lanthanum titanate–cobalt iron oxide composite thin films

We have investigated the electrical and magnetic properties of solution synthesized Pb0.85La0.15TiO3–CoFe2O4 composite thin films. These composite films exhibit both polarization as well as magnetic hysteresis characteristics at room temperature. The dielectric constant of the composite films is found to increase remarkably up to 6.0 vol% CFO contents. The increase of the dielectric constant and loss tangent follow a general percolation model originally developed for metal–ceramic composites. It is argued that Maxwell–Wagner polarization, as well as diffusion of transition metal cation(s) from CFO to PLT15 lattice are responsible for the percolative behavior of the dielectric properties in these films.

Research highlights
► PLT:CFO composite films are synthesized by sol–gel route.
► Composite films exhibit room temperature ferroelectric and (ferri)magnetic ordering.
► The increase of the dielectric constant and loss tangent follow percolative behavior.
► The percolative behavior is due to Maxwell–Wagner polarization, and cation diffusion.