Recent development in piezoelectric materials
used for actuators and sensors applications
Dragan Damjanovic,
Ceramics Laboratory, Materials Institute
Swiss Federal Institute of Technology - EPFL
Lausanne
ECOLE POLYTECHNIQUE
FEDERALE DE LAUSANNE
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Outline
•
•
•
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What is new in piezoelectric materials?
New ideas about morphotropic phase boundary
Improvement in piezoelectric properties
Why is the new knowledge on crystals important
for ceramics?
• Open questions
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“New” piezoelectric materials
Pb(Zn1/2Nb2/3)O3-PbTiO3, P(Mg1/2Nb2/3)O3-PbTiO3
BiMeO3-PbTiO3
langasite, GaPO4
KNbO3
Na0.5Bi0.5TiO3
textured ceramics
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Perovskite structure ABO3
PbTiO3
O
A+1...+3 B+3…+6
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Pb(Zn1/2Nb2/3)O3-PbTiO3, Pb(Mg1/2Nb2/3)O3-PbTiO3
single crystals
[001]c
[111]c
rhombohedral
d33>2000 pC/N
k33>0.9
diel permittivity 2000-9000
d15>4000 pC/N
excellent
for transducer arrays
and actuators
Park, Shrou 1997t
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Transducer applications
arrays
1DIM
-better images
-higher resolution
-higher bandwidth
15-20%-…?
2DIM
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Advantages of relaxor-ferroelectric single crystals
zero or small strain-field hystersis
large strain
excellent for actuator applications
[001]c
[111]c
E
E
rhombohedral
weak field d33 2500 pm/V
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Large piezoelectric effect in ferroelectric single crystals
along nonpolar directions: eg. d33,d31, k33, k31
Park, Shrout (PMN-PT,PZN-PT)
Wada (BaTiO3)
Nakamura (KNbO3)
Du, Belegundu Uchino (PZT)
Taylor, Damjanovic (exp. PZT films)
large properties
observed near the
morphotropic phase
boundary
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Multidomain vs. Monodomain crystal
-experimental data PMN-0.33PT
Measurement
direction
0
0
0 146 0⎞
⎛ 0
[ 001]
dij c = ⎜ 0
0
0
146 0 0⎟
⎜
⎟
0 0⎠
⎝ −1330 −1330 2820 0
R. Zhang, B. Jiang, and W. Cao,
J. Appl. Phys 90, 3471 (2001)
?
Measurement
direction
0
0
0
4100 −2680⎞
⎛ 0
[111]
dij c = ⎜ − 1340 1340 0 4100
0
0 ⎟
⎜
⎟
0
0
0 ⎠
⎝ −90 −90 190
R. Zhang, B. Jiang, and W. Cao,
Appl.Phys.Lett 82, 787 (2003)
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Results of calculations for a monodomain
crystal of 0.67PMN-0.33PT
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Multidomain vs. Monodomain crystal
result of calculations
[001]c
d33
= 2800 pm /V
[001]c
d31
= 1300 pm /V
experiment
100%
[001]c
d33
= 2310 pm /V
82%
[001]c
d31
= 1150 pm /V
88%
calculations
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Monodomain vs multidomain response
-the multidomain state (engineered domain state)
contributes little to the piezoelectric d31 and d33
coefficients of 0.67PMN-0.33PTsingle crystals along
[001]c=[111]r axis.
-At least 82-88%of the large piezoelectric response
along [001]c=[111]r axis in multidomain rhombohedral
crystal is due to piezoelectric anisotropy
(large shear coefficients), i.e.intrinsic lattice effects of
a single domain.
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Domain wall engineering
P
A
200µm
(b)
(a)
200µm
P
A
(c)
10 4
10 4
90
90
60
-30
|Z| / Ω
|Z| / Ω
0
1000
30
0
1000
-30
-60
100
500
600
-90
700
Frequency / kHz
coarse domains
Phase / deg.
30
60
Phase / deg.
Wada
BaTiO3
(2003)
200µm
-60
100
500
600
-90
700
Frequency / kHz
fine domains
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Tokyo
TokyoTech.
Tech.
4mm BaTiO3 single crystals
[111]c direction
[111]
E-field
[010]c
Schematic Domain Configuration
90˚ domain wall of (011)c
[001]c
Satoshi
Wada
Tokyo
Institute
of Techn.
[111]c
[011]c
Combination
Combination of
of charged
charged && uncharged
uncharged 90˚
90˚ domain
domain walls
walls
[211]c
Same domain configurations of these BaTiO3 crystals
But
These crystals have different densities of 90˚ domain walls
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TokyoTech.
Tech.
4mm BaTiO3 single crystals
Table I Piezoelectric properties of the BaTiO3 single crystals poled along [001]c and [111]c
directions.
Satoshi
Wada
Tokyo
Institute
of Techn.
s11 E
d31
k31
BaTiO 3 single crystals
ε33 T
(pm2/N)
[001] c a)
(single-domain)
129
7.4
-33.4
---
---
---
-62.0
---
[111] c
(domain size > 40µm
2,185
7.37
-97.8
25.9
[111] c
(domain size of 13.3µm
2,087
7.68
-134.7
35.7
[111] c
(domain size of 6.5µm
2,441
8.80
-180.1
41.4
[111] c
(domain size of 5.5µm
2,762
9.58
-230.0
47.5
1,700
16.4
-171.0
34.4
(pC/N)
(%)
b)
[111] c
(single-domain)
”soft“ PZT ceramics
c)
Pb 0.988(Ti 0.48Zr 0.52) 0.976Nb 0.024O 3
a): measured by Zgonik et al.
b): calculated using the values measured by Zgonik et al.
c): measured by Jaffe et al.
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Piezoelectric coefficient (pC/N)
PZT ceramics
500
C
P
Temperature (°C)
400
T
300
A
T
F
R (high)
F
200
rhombohedral
tetragonal
100
R (low)
O
A
F
0
0
PbZrO
20
3
40
60
mol% PbTiO
80
3
100
PbTiO
3
500
400
d15
300
d33
200
d31
100
0
48
50
52
54
56
58
60
mol% PbZrO
3
high properties associated with
the presence of the MPB
8 directions
6 directions
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Relaxor-ferroelectric compositions
P(Zn1/2Nb2/3)O3-PbTiO3, P(Mg1/2Nb2/3)O3-PbTiO3
morphotropic phase boundary is
present in many complex systems
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Morphotropic phase boundary
500
-can be strongly curved
a monoclinic/orthorhombic
phase separates rhombohedral and
tetragonal phases
Temperature (°C)
-not a narrow boundary between tetragonal
and rhombohedral phases;
C
P
400
T
300
A
T
F
R (high)
F
200
rhombohedral
tetragonal
100
R (low)
O
A
F
0
0
PbZrO
20
3
40
60
mol% PbTiO
3
80
100
PbTiO
3
monoclinic
Noheda, Shirane
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Similarity between temperature and composition
phase diagrams
M
PZT
R
T
R
T
barium titanate
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Why piezoelectric properties become
exceptionally high along a nonpolar direction?
Shear effect
Electric
field
P
d33
d15
P
Longitudinal effect
Transverse effect
Electric
field
d31
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Why piezoelectric properties become
exceptionally high along a nonpolar direction?

ϑ
P
ϑ
P
P

d ∗33 (ϑ ) = a3i a3 j a3k dijk
d33* (ϑ ) = cos ϑ ( d15t sin 2 ϑ + d31t sin 2 ϑ + d33t cos 2 ϑ )
tetragonal
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Permittivity and shear piezoelectric coefficientsCase of BaTiO3
t
t
t
d15
= d 24
= ε 0η11
Q44 P3t
R
O/M
o
o
d15
= ε 0η11
Q44 P3o
T
pre-transitional
behavior
o
o
d 24
= 2ε 0η22
(Q11 − Q12 )P3o
r
d15
1
r
= ( 4Q11 − 4Q12 + Q44 )ε 0 P3r η11
3
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Tetragonal BaTiO3 on cooling toward the orthorhombic
phase
d33(T)
PT
PO
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Orthorhombic BaTiO3 on cooling from tetragonal toward
the rhombohedral phase
d33(T)
PT
PO
PO
PR
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Rhombohedral BaTiO3 on cooling from the orthorhombic
phase
d33(T)
PR
Po
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Origin of large d15
d15 becomes high near
a phase transition
induced by temperature
Budimir, Damjanovic
d15 becomes high near
a phase transition
induced by composition
change
d15 becomes high
near phase transitions induced
by electric field
Haun
Bellaiche
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Origin of large d15
d15 is large when polarization can rotate easily
Ortho.Tetr.
Tetr.Ortho.
Ortho.Rhomb.
Rhomb.-Ortho.
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Origin of large piezoelectric activity along
nonpolar directions
1. in proximity of phase transitions induced by
temperature
composition
field
some materials possess very large shear piezoelectric coefficients
large shear coeff. ⇒ large d33, d31 along nonpolar axes
This mechanism is not related to the presence of engineered domain
structure!
2. high density of engineered domain states can further increase
response given by mechanism 1. (result of Satoshi Wada; ECP)
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Permittivity arguments
t
d15
=
t
d 24
t
= ε 0η11
Q44 P3t
o
o
d15
= ε 0η11
Q44 P3o
o
o
d 24
= 2ε 0η22
(Q11 − Q12 )P3o
r
d15
1
r
= ( 4Q11 − 4Q12 + Q44 )ε 0 P3r η11
3
shear d coefficients are high
because permittivity perpendicular
to polarization is high;
as a consequence of high
permittivity perp. to polarization,
the polarization rotation is high
T
⎛ P1ind ⎞ ⎛ 0 ⎞ ⎛ε11
⎞ ⎛ E1 ⎞
⎜ ind ⎟ ⎜ ⎟ ⎜
⎟⎜E ⎟
P
=
0
+
ε
2
22
2
⎜
⎟ ⎜ ⎟ ⎜
⎟
⎜
⎟
⎜ P ind ⎟ ⎝ P ⎠ ⎝
ε 33⎠ ⎝ E 3⎠
3
⎝ 3 ⎠
[001]C
O
R
[101]C
[111]C
MB
MC
MA
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Free energy arguments
500
T
C
P
400
O
R
[101]C
[111]C
MB
MC
Temperature (°C)
[001]C
T
300
A
T
F
R (high)
F
200
rhombohedral
tetragonal
100
R (low)
O
A
MA
F
0
0
PbZrO
20
40
60
mol% PbTiO
80
3
3
100
PbTiO
3
G
R
polarization rotates easily
in the composition range where
the free energies of different phases
are close
M
T
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Electric field effects on piezoelectric anisotropy
in perovskite materials
BaTiO3
t
t
t
d15
= d 24
= ε 0η11
Q44 P3t
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Electric field effects on piezoelectric anisotropy
in perovskite materials
at 285 K
at 365 K
d33* (ϑ ) = cos ϑ ( d15t sin 2 ϑ + d31t sin 2 ϑ + d33t cos 2 ϑ )
Budimir,
Damjanovic 2004
DC Field applied anti parallel to polarization increases
piezoelectric effect
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Absence of phase transitions-case of PbTiO3
No phase transitions: small d15, small d31,small d33 !!!
Anisotropy is not a function of the temperature
PT
d33(θ)
80 K
300 K
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Why are properties high at the MPB in ceramics?
Usual textbook explanation of the large piezoelectric
response at MPB:
-ease of domain re-orientation (8 rhombohedral, 6 tetragonal,
24 monoclinic states)
-large remanent polarization
-extrinsic contributions from
moving domain walls
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What happens in ceramics?
d33 only
some grains
d15, d33 and d31
most of the grains
*
r
r
d33
cos ϑ sin 2 ϑ + d22
sin 3 ϑ cos 3ϕ +
(ϑ ,ϕ ) = d15
r
r
+d31
sin 2 ϑ cosϑ + d33
cos3 ϑ
(d33)ave of misoriented grains is high if d15 of the single crystal is high.
d15 is high near phase transitions induced by temperature, composition,
or field.
Therefore, importance of MPB!
Hint how to design better materials.
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Evolution of d33 surface in rhombohedral PZT
with composition
PZT 90/10
Anisotropy
increases as
MPB is approached
PZT 60/40
PR
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Open problems with relaxor-ferroelectrics
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Properties of relaxor-ferroelectric materials near MPB
O/M
MPB
PMN-PT
R
T
PMN
PT
low temperature operation
PNN-PT-PZ
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Alternative: BiScO3-PbTiO3 single crystal
Zhang, Randall, Shrout
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Hysteresis is sometimes present, especially in the
presence of clamping stresses
converse effect
direct effect
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Lead free materials: (K,Na)NbO3 ceramics
KNN
biocompatibility
kt>40%
d33>100 pC/N
ρ= 4.5 gr/cm3
LEAF FP5 project
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Lead free materials
(KNaLi)(NbTaSb)O3
-a morphotropic phase boundary exists in LiTaO3-KNaNbO3
system
-kp as large as 60%
-d33>300 pC/N
-strain comparable to that in PZT for the same driving field
patents by Toyota 2003,2004
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Conclusions
-exciting new developments
-our knowledge of perovskite materials is huge,
but new, important discoveries are still being made
-what are the requirements for high performance?
new hints!
-new, high performance materials are being developed
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