Transcript ppt file - University of Florida

Domain Wall Evolution in Phase
Transforming Oxides
cit
y
sion
Mechanical
Stress
oe
lec
tri
sm
eti
ag
n
ism
et
ectricity
xpan
mal E
Ther
n
ag
om
Magnetoel
– One of the fundamental structural features that
defines functionality in these materials are domain
walls (see figure).
– However, very few experiments are currently able
to characterize domain wall evolution during real
operating conditions of sensors and actuators
(e.g., cycling fields of low amplitude).
ez
Pyr
ez
oele
ctri
city
Pi
• Scientific challenge
Magnetization
Pi
– Sensors and actuators are used in several military
functions including surveillance, reconnaissance,
navigation, etc.
– Phase-transforming oxides, including ferroelectric
materials, exhibit unique potential for multi- Temperature
Change
functionality (see figure).
Py
rom
• Motivation
Jacob L. Jones, University of Florida
Electric Field
Ps
Ps
Domain Wall Evolution in Phase
Transforming Oxides
• Objectives
1. to enhance the basic
understanding which
underlies the linkage
between domain
architectures and
macroscopic properties
(structure-property
relationships) in bulk, phasetransforming oxides,
2. to explore new methods to
control domain structures,
and
3. to identify unique domain
configurations with previously
unrealizable properties.
Jacob L. Jones, University of Florida
Macroscopic property
(e.g., e-field-induced
strain)
grain boundary
domain
domain wall
motion
piezoelectric
effect
V
Domain Wall Evolution in Phase
Transforming Oxides
• Approach
Jacob L. Jones, University of Florida
– Utilize advanced, real-time
characterization techniques including
in situ X-ray and neutron diffraction
during thermal, electrical, mechanical,
and/or magnetic field application.
– These unique in situ measurements
of domain wall behavior then provide
insights into materials development
for enhanced functionality.
– Prior state-of-the-art involved
application of static electric fields
at high electric field amplitudes.
– Our approach involves studying domain wall motion during
dynamic loading and at operation-relevant field amplitudes
(often below the coercive field).
d33(pm/V)
(a)
600
Domain Wall Evolution in Phase
Transforming Oxides
Lattice strain
400
200
• Scientific Accomplishments
Strain
from L. Jones,
Jacob
90domain wall motion
Strain from 90do
wall motion
Cumulative strain
90  domain wall m
and electric-field
lattice strain
University of Florida
Cumulative contributions Cumulative contributions
Fractional nonlinear
(pm/V)
to d33 (pm/V)
to d33d33
(pm/V)
contribution
linear
on
Diffracted Intensity
Apparent piezoele
800
coefficient
(a)
– Time-resolved observation of800
domain
variants
{002}/{200}
of
Strain from 90do
(b)
tetragonal Pb(Zr,Ti)O3 ceramics
of wall motion
600 demonstrate the motion
ion
t
u
b
i
r
from latticestrain
Cumulative
600 walls duringarapplication
cont
ferroelectric/ferroelastic domain
of
weak
e
Lattice
strain
n
li
strain
90
 domain wall m
Non
400
n
and electric-fieldutio
electric field amplitudes.
ontrib
c
400
r
a
e
lattice strain
Lin
– Quantitative analysis of diffraction
data
leads to
a complete account
200
Strain from
ntribution
o
c
r
a
e
from 90  domain
n
li
on
200
90Ndomain wallcoefficient,
motion
of the contributions to the ceramic
piezoelectric
dwall
33. motion
Linear contribution
Relative Contributions:
800
(b)
Respective nonlin
(c)
0.4
contributions calc
ution
b
i
r
t
from lattice
n
o
600
c
from (a) and (b)
r
linea
strain
0.3
Non
tion
ibustrain
Lattice
r
t
n
o
c
400
Linear
0.2
ntribution
o
c
r
a
e
from 90  domain
n
li
Non
200
-E
3.87
0.1
Strain
from
90

0.0
wall motion
+E
3.97
2 
Linear
contribution
-E
0.5
de
domain wall motion
nds
gre
1.0
e co
es) 4.07
s
0.0
,
e
Respective nonlin
Tim
200
400
600
800
(c)
0.4 Electric Field Amplitude (V/mm)
contributions calc
from (a) and (b)
Measurement performed
at the European Synchrotron Radiation
Facility
0.3
d33(pm/V)
(a)
600
Domain Wall Evolution in Phase
Transforming Oxides
Lattice strain
400
200
• Scientific Accomplishments
–
coefficient in this
wall motion, not the
Cumulative contributions Cumulative contributions
Fractional nonlinear
(pm/V)
to d33 (pm/V)
to d33d33
(pm/V)
contribution
–
University of Florida
Apparent piezoele
800
coefficient
(a)
The linear component of the 800
e-field-induced
lattice
strains
is
the
Strain from 90do
(b)
wall motion
only component which may be
600 intrinsic piezoelectricity
ion (since
t
u
b
i
tr
from latticestrain
Cumulative
600
r con
a
intrinsic PE is field-independent).
e
Lattice
strain
n
li
strain
90
 domain wall m
Non
400
n
and electric-fieldutio
Closer inspection of lattice strain
ontrib indicate this is not
c
400 measurements
r
a
e
lattice strain
Lin
likely the intrinsic piezoelectric
but orather
an elastic
200 coefficient,
Strain from
ntribution
c
r
a
e
from 90  domain
n
li
on
200
90Ndomain wall motion
intergranular coupling.
wall motion
Linear contribution
Remarkably, the
Relative Contributions:
800
(b)
Respective nonlin
piezoelectric d33
(c)
0.4
contributions calc
ution
b
i
r
t
from lattice
n
o
600
c
from (a) and (b)
r
linea
strain
0.3
Non
common soft PZT
tion
ibustrain
Lattice
r
t
n
o
c
400
Linear
0.2
composition is mostly
ntribution
o
c
r
a
e
from 90  domain
n
li
attributed to domain
Non
200
0.1
Strain from 90 
wall motion
Linear
contribution
domain wall motion
0.0
intrinsic piezoelectric
Respective nonlin
200
400
600
800
(c)
0.4 Electric Field Amplitude (V/mm)
contributions calc
effect of the lattice.
from (a) and (b)
In review 0.3
as a Feature Article for J. American Ceramic
Society
linear
on
–
Strain
from L. Jones,
Jacob
90domain wall motion
Strain from 90do
wall motion
Cumulative strain
90  domain wall m
and electric-field
lattice strain
Domain Wall Evolution in Phase
Transforming Oxides
• Scientific Accomplishments
Jacob L. Jones, University of Florida
– Synthesis, high-resolution structural measurement, and refinement of
(1-x)Na0.5Bi0.5TiO3-xBaTiO3 (BNT-xBT) piezoelectric ceramics.
– Crystallographic refinement of the NBT indicates a monoclinic Cc
space group, not widely-assumed R3c.
– Implies complex ferroelectric/ferroelastic domain structure in BNTbased materials. May explain nanodomains and relaxor-like behavior.
– Also suggests “monoclinic” not a sufficient condition for high d33.
High-resolution X-ray measurements at the Advanced Photon Source, Argonne National Laboratory
Domain Wall Evolution in Phase
Transforming Oxides
• Scientific Accomplishments
Jacob L. Jones, University of Florida
d33 (pm/V)
– Acceptor-doping in Na0.5Bi0.5TiO3(BNT)-based ceramics show
unexpected behavior of thermal stability.
Enhanced thermal stability
– Piezoelectric coefficient
140
d33 as a function of
Undoped
0.5 mol% Fe O
120
temperature shows
1.0 mol% Fe O
increased thermal stability
1.5 mol% Fe O
100
2.0 mol% Fe O
for small (<1%) Fe2O3
80
doping concentration.
– Because of negligible
60
lowering of initial
40
(room temperature) d33,
this material has a high
20
piezoelectric coefficient at
0
elevated temperatures.
0
50
100
150
200
250
300
350
Temperature (degrees C)
2
3
2
3
2
3
2
3
Domain Wall Evolution in Phase
Transforming Oxides
• Transitions
Jacob L. Jones, University of Florida
– The PI gave several seminars at national
laboratories including:
• User Science Seminar, Advanced Photon
Source, Argonne National Laboratory,
July 30, 2010.
• Lujan Neutron Scattering Center, Los Alamos
National Laboratory, July 27, 2010.
– The PI participated and delivered an invited
talk at a symposium organized by ARL
PI Jones and PhD student
personnel from the Aberdeen Proving Ground
Elena Aksel at Los Alamos
National Laboratory
(XIX International Materials Research Congress,
Cancun, Mexico, August 15-19, 2010.)
– The PI hosted Dr. Melanie Cole from the Army Research Laboratory,
Aberdeen Proving Ground, on Sept 12, 2008. She met with several faculty
members and the PI and gave a departmental research seminar titled,
“Compositionally Tailored Material Properties To Enable Performance
Enhanced Tunable Microwave Devices.”
Domain Wall Evolution in Phase
Transforming Oxides
• PI Awards
Jacob L. Jones, University of Florida
– Presidential Early Career Award for Scientists and Engineers
(PECASE), Awarded January 13, 2010.
– Defense Program Awards of Excellence, nominated through the
Los Alamos National Laboratory and presented by Donald Cook
(Deputy Administrator for Defense Programs, NNSA), August 30,
2010, “for discovering important new physics in ferroelectric
ceramics used in neutron generators through clever neutron
scattering experiments.”
– Faculty Excellence Award, April 22, 2010. Department of Materials
Science and Engineering, University of Florida.
– Excellence Award for Assistant Professors, April 27, 2010, one of
10 recipients at the University of Florida.
– 11 invited talks acknowledging ARO support at international
conferences, national laboratories, and universities.
Domain Wall Evolution in Phase
Transforming Oxides
Jacob L. Jones, University of Florida
• Future Research Plans
PLZT Longitudinal Strain in Response
to Instantaniously Applied E-Fields
Normalized Longitudinal Strain
– Recent time-dependent pulse
poling measurements
discriminate between 180°
and non-180° domain wall
motion (see figure).
– Use of pulsed electric fields of
various durations during the
electrical poling process will
coerce domains into unique
configurations.
– This time-dependent
experiment builds upon our
existing electromechanical
poling studies.
1
2.0 kV/mm
1.9 kV/mm
1.8 kV/mm
1.6 kV/mm
1.5 kV/mm
1.4 kV/mm
0.8
0.6
0.4
0.2
0
0
10
2
4
10
10
Time (microseconds)
6
10
180° domain switching occurs
first during pulsed fields
Non-180° domain switching occurs
last after pulsed field application
Domain Wall Evolution in Phase
Transforming Oxides
• Future Research Plans
– Analysis of structure and resulting
domain structures in BNT-xBT using
high-resolution X-ray diffraction.
– In situ X-ray and neutron diffraction
measurements to understand origin
of electromechanical behavior at
x=7.
– We hypothesize that high
piezoelectric d33 at x=7 is not
related to the morphotropic phase
boundary, but due to domain wall
contributions (similar to PZT).
– This implies that the design of highd33 ceramics should include domain
wall contributions.
Jacob L. Jones, University of Florida
Peak in permittivity
and d33 at x=7
W. Jo, J. L. Jones, et al., in review at J. Applied Physics