Ferroelectric films with composition gradients normal to the substrate have recently been reported to exhibit anomalously large polarization offsets when hysteresis loops are driven with an ac voltage and measured using a Sawyer-Tower (ST) circuit. These offsets have been reported in graded Pb(Zr, Ti)O3 (over 400 μC/cm2) and graded (Ba, Sr)TiO3 (30 μC/cm2) films. In this work, it was found that the offset observed in graded Pb(Zr, Ti)O3 films can be attributed to development of a dc voltage across the ac-voltage driven film, rather than a polarization offset. Recognition of this result reduces these previously reported offset values by a factor of Cs/Cref, where Cref and Cs are the reference and sample capacitances, respectively, used in the ST circuit. These dc-voltage offsets still represent a phenomenon which may lead to novel device applications.
|Number of pages||3|
|Journal||Applied Physics Letters|
|Publication status||Published - 11 Jan 1999|
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)