Doping and thickness effects on dielectric properties and subswitching behavior of lead titanate thin films

Dielectric and ferroelectric properties of sol-gel derived PbTiO3 and (Pb,Er)TiO3 films with thickness in the range from 134 to 420 nm have been investigated. It is demonstrated that 1% Er doping improves the shape of the ferroelectric hysteresis loop probably due to compensation of p-type conductivity. The dielectric constant is shown to be linearly dependent on the amplitude of the measuring signal. It is shown that the Rayleigh equation can be used to discriminate between reversible and irreversible contributions to the dielectric properties of the films. Both reversible and irreversible Rayleigh components were found to be affected by donor doping and film thickness. Introducing 1% of Er is thought to counteract domain wall pinning on “dead layer” near the film–electrode interface.