Permittivity scaling in Ba_1-xSr_xTiO₃ thin films and ceramics

A dramatic enhancement in the electromechanical response of barium titanate thin films is demonstrated by understanding and optimizing the relationship between organic removal, crystallization, and microstructure, which therefore results in pore elimination, larger grain sizes, and superior densification. The combination enables one to produce bulk-like dielectric properties in a thin film with a room temperature permittivity value above 3000. This advancement in complex oxide thin film processing science creates a new perspective from which to compare, parameterize, and better understand a collection of literature data concerning the manner in which the dielectric response of BaTiO₃ depends upon physical dimensions. We are consequently able to apply a single physical model to bulk ceramic and thin film systems, and so demonstrate that the existence of parasitic interfacial layers are not needed to explain dielectric scaling. This work is instrumental in illustrating that extrinsic contributions to scaling are predominant, and that a fundamental understanding of material synthesis provides important opportunities to broaden the spectrum of nonlinear electromechanical properties that can be achieved in ferroelectric thin films.