Abstract
Ferroelectrics are intensively studied materials due to their unique properties with high potential for applications. Despite all efforts devoted to obtain the values of ferroelectric material constants, the problem of the magnitude of static dielectric constant remains unsolved. In this article it is shown that the value of the static dielectric constant at zero electric field and with negligible contribution from the ferroelectric polarization (also called static background dielectric constant, or just background dielectric constant) can be very low (between 10 and 15), possibly converging towards the value in the optical domain. It is also found that the natural state of an ideal, mono-domain, epitaxial ferroelectric is that of full depletion with constant capacitance at voltages outside the switching domain. The findings are based on experimental results obtained from a new custom method designed to measure the capacitance-voltage characteristic in static conditions, as well from Rayleigh analysis. These results have important implications in future analysis of conduction mechanisms in ferroelectrics and theoretical modeling of ferroelectric-based devices.
Highlights
Ferroelectric materials have been studied for the better part of the last 100 years, the magnitude of the static dielectric constant of these materials is still a matter of debate and controversy
It is fair to consider that the static dielectric constant in ferroelectric materials is very much sample dependent, being affected by extrinsic contributions coming from various structural defects that may act as trapping centers for electric charges that may be able to respond to the small amplitude ac signal used for standard capacitance measurements[8]
The static dielectric constant, when there is no contribution from ferroelectric polarization, is sometimes called background static dielectric constant and should be related to the linear dielectric response associated to any non-ferroelectric material[39,40]
Summary
Ferroelectric materials have been studied for the better part of the last 100 years, the magnitude of the static dielectric constant of these materials is still a matter of debate and controversy. It is fair to consider that the static dielectric constant in ferroelectric materials is very much sample dependent, being affected by extrinsic contributions coming from various structural defects that may act as trapping centers for electric charges that may be able to respond to the small amplitude ac signal used for standard capacitance measurements[8]. The problem that arises is the parasitic contributions appearing in the measured capacitance due to transitory phenomena induced by the step change of the dc voltage (e.g. charge carriers released from traps able to respond to the frequency and amplitude of the ac voltage)[38] All these issues will be reflected in the value of the calculated dielectric constant!. The static dielectric constant, when there is no contribution from ferroelectric polarization, is sometimes called background static dielectric constant and should be related to the linear dielectric response associated to any non-ferroelectric material[39,40]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
