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Manipulating Ferroelectrics through Changes in Surface and Interface Properties
journal contribution
posted on 2017-10-23, 00:00 authored by Nina Balke, Ramamoorthy Ramesh, Pu YuFerroelectric
materials are used in many applications of modern technologies including
information storage, transducers, sensors, tunable capacitors, and
other novel device concepts. In many of these applications, the ferroelectric
properties, such as switching voltages, piezoelectric constants, or
stability of nanodomains, are crucial. For any application, even for
material characterization, the material itself needs to be interfaced
with electrodes. On the basis of the structural, chemical, and electronic
properties of the interfaces, the measured material properties can
be determined by the interface. This is also true for surfaces. However,
the importance of interfaces and surfaces and their effect on experiments
are often neglected, which results in many dramatically different
experimental results for nominally identical samples. Therefore, it
is crucial to understand the role of the interface and surface properties
on internal bias fields and the domain switching process. Here, the
nanoscale ferroelectric switching process and the stability of nanodomains
for Pb(Zr,Ti)O3 thin films are investigated by using scanning
probe microscopy. Interface and surface properties are modulated through
the selection/redesign of electrode materials as well as tuning the
surface-near oxygen vacancies, which both can result in changes of
the electric fields acting across the sample, and consequently this
controls the measured ferroelectric and domain retention properties.
By understanding the role of surfaces and interfaces, ferroelectric
properties can be tuned to eliminate the problem of asymmetric domain
stability by combining the effects of different electrode materials.
This study forms an important step toward integrating ferroelectric
materials in electronic devices.