Dielectric nonlinearity and loss in ferroelectric thin films

Pulsed laser deposition has been used to deposit multilayer heterostructures consisting of high temperature superconductor (HTS) and ferroelectric layers for tunable microwave device applications. The dielectric nonlinearity and loss of the ferroelectric thin films are the key material parameters determining the performance of the tunable devices and hence the feasibility of this technology. In this paper, I will summarize the current understanding of these issues and outline the strategies to study these problems.