Simple model of SBN single crystal—electrode interfacial layer

Abstract

Contact effects (Au-electrodes) in ferroelectric Sr_3/44Ba_1/4Nb₂O₆(SBN) result in a thickness dependence of the measured dielectric constant and loss. The contribution of contact and bulk dielectric properties is separated using the series of two parallel RC circuits for electric field both parallel and perpendicular to the ferroelectric axis. The temperature as well as the frequency dependence of the bulk and surface dielectric properties are different. The particular dielectric properties of the surface layer are accounted for by electrical inhomogeneities within the contact region. The types of possible inhomogeneities are evaluated using finite element method computer simulations. The best agreement between experimental measurements and a two-dimensional RC net computer simulation were achieved calculating the model with holes and reoriented RC elements under the electrodes.

Key Words:

• strontium barium niobate
• dielectric properties
• bulk-electrode interface
• electrodes
• computer simulation