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@INPROCEEDINGS{Wrdenweber:819684,
author = {Wördenweber, Roger and Schwarzkopf, Jutta and cai, biya
and Dai, Yang and Braun, Dorothea and Schubert, Jürgen},
title = {{S}train {E}ngineered {F}erroelectric {O}xides: {A}
{P}ossible {R}oute to {I}mproved or even {N}ovel
{A}pplications},
reportid = {FZJ-2016-05291},
year = {2016},
abstract = {Due to their tendency to form ionic states, oxides of the
3d transition metal are (i) highly interesting for various
applications and (ii) can easily be affected by relatively
simple means. Well known examples are high-temperature
superconductors (Tc > 100K), superisolators ( > 1012
m), or high-k material ( > 20000). Especially the
latter – i.e. ferroelectric oxides - show extremely high
permittivity and piezoelectricity however only close to the
phase transition To which is typically far below or above
room temperature. Therefore it is of interest to shift To
towards room temperature without loosing too much of the
extraordinary properties of the ferroelectric oxide.In this
contribution I will present a way to engineer the transition
temperature, the permittivity and the conductivity of
epitaxially grown oxide films via strain. Anisotropic
biaxial strain (tensile or compressive) is generated in
NaNbO3 and SrTiO3 films (20-100nm) via epitaxially growth on
single-crystalline oxide substrates with different lattice
mismatch. Generally, tensile in-plane strain leads to an
increase of the ferroelectric in-plane transition
temperature whereas compressive strain tends to decrease the
transition temperature. Shifts of the transition temperature
by several 100K can easily be obtained via this method
leading to room-temperature permittivity of several 1000.
The phase transition itself and the ferroelectric states of
the anisotropically strained films turn out to be highly
complex. First, the transition temperature depends on the
direction of the applied electric field which contradicts
the concept of an uniform phase transition for a given
system. Second, all systems, that we examined, showed
relaxor properties which are usually expected for systems
consisting of a mixture of phases. Third, most ferroelectric
properties strongly depend on the applied electric field.
The different observations are discussed in terms of
existing models. Furthermore I will sketch possible concepts
and first attempts to use these systems for instance for
improved sensor devices (e.g. thin films SAW sensors), data
storage or even exotic novel concepts like artificial
synapses.},
month = {Apr},
date = {2016-04-06},
organization = {TO-BE Spring Meeting 2016, Warwick
(United Kingdom), 6 Apr 2016 - 8 Apr
2016},
subtyp = {Invited},
cin = {PGI-8 / JARA-FIT / PGI-9},
cid = {I:(DE-Juel1)PGI-8-20110106 / $I:(DE-82)080009_20140620$ /
I:(DE-Juel1)PGI-9-20110106},
pnm = {523 - Controlling Configuration-Based Phenomena (POF3-523)},
pid = {G:(DE-HGF)POF3-523},
typ = {PUB:(DE-HGF)6},
url = {https://juser.fz-juelich.de/record/819684},
}