Analysis of the Switching Characteristics of PZT Films by First Order Reversal Curve Diagrams

Abstract

A new type of characterization of ferroelectric switching using First Order Reversal Curve (FORC) diagrams based on recording of minor hysteresis loops has been recently proposed. We apply this method to polycrystalline and epitaxial PZT thin films measured under various conditions and compare them to PZT ceramics. In each case we have been able to separate the reversible and irreversible contributions to switching and discuss the most dominant of them in relation to hysteresis loop shapes and ferroelectric switching mechanisms. The FORC diagrams of fatigued PZT exhibit features in agreement with its hysteresis probed at nanoscale and confirm a degradation mechanism based on local imprint. The asymmetrical tail present on measured FORC diagrams has been explained in terms of a nucleation-growth switching process triggered by latent nuclei. All these findings attest the usefulness of the FORC diagrams for both characterizing various types of samples as well as the elucidation of ferroelectrics’ physics.

Keywords:

• ferroelectrics
• switching
• hysteresis
• minor loops
• FORC diagrams

ACKNOWLEDGEMENT

We are grateful to Prof. Susumu Horita from JAIST for supplying the epitaxial PZT film.