Introduction to the special issue on Nanoscale Ferroelectrics

Abstract

As ferroelectrics-based devices are entering the realm of nanoscale dimensions, it is expected that properties of ferroelectrics will start exhibiting a pronounced size effect due to high surface-to-volume ratio, increased effect of local nonstoichiometry and interfaces, polarization fluctuations, etc. This poses serious problems to the development of nanoscale ferroelectric-based devices, such as high-density non-volatile memories, photonic and electrooptic devices, piezoelectric sensors an da ctuators, smart systems, and probe-based storage devices. Apparently, advances in understanding the nanoscale ferroelectric phenomena have not been following the progress in deposition and nanofabrication techniques at a sufficiently high pace. Research on various aspects of nanoscale ferroelectric phenomena is receiving great attention from scientific community. Hundreds of papers are published every year in different journals devoted to physics, chemistry, materials science, microelectronics, etc. In this Special Issue, to provide an overview of the current status in nanoscale ferroelectric research, the editors are bringing together review papers on subjects ranging from processing of ferroelectric nanoislands to theoretical analysis of the switching of polarization in confined geometries to realspace characterization of ferroelectric structures. Several papers in this Special Issue are devoted to fabrication of ferroelectric nanostructures using sol-gel method that allows forming isolated nanoislands where the properties of ferroelectrics can be investigated as a function of their size. Modeling of the nanostructures including domain switching and stress-mediated effects is also presented. Recent progress in an understanding of dielectric anomaly in ultrathin capacitors is discussed. Development in characterizing domain configurations in 3-D shape-constrained ferroelectrics fabricated by ion etching is also presented. The current status of Piezoresponse Force Microscopy (PFM) as a reliable tool for probing nanoscopic ferroelectric structures is overviewed in this Issue. Further insights into highorder frequency and geometry effects in PFM are presented as well.