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2016 APL The evolution mechanism of defect dipoles and high strain in MnO2-doped KNN leadfree ceramics-si

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The evolution mechanism of defect dipoles and high strain in
MnO2-doped KNN lead-free ceramics
Zhihao Zhao,1 Yejing Dai,1,a) Xiaolei Li,1 Zhe Zhao,1 and Xiaowen Zhang2
1Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, School
of Material Science and Engineering, Tianjin University, Tianjin, 300072, PR China
2The State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and
Engineering, Tsinghua University, Beijing 100084, PR China
Fig. S1. (Color online) Temperature dependence of relative dielectric constant and
dielectric loss of KNN-xMn ceramics sintered in air and Ar atmosphere at different
frequency.
a) Author to whom correspondence should be addressed. Electronic mail: daiyj04@tju.edu.cn.
Table S1 Dielectric properties of KNN-xMn ceramics sintered in air and Ar
atmosphere at different frequency.
The temperature dependence of dielectric constant and dielectric loss from 25 to 450
C with a heating rate of 1 C/min were measured at 1 kHz, 10 kHz and 100 kHz,
using an HP4284A Precision impedance analyzer (Hewlett-Packard, Palo Alto, CA)
with an automated temperature control unit.
Fig. S1 shows the temperature dependence of relative dielectric constant εr and
dielectric loss tanδ of KNN-xMn ceramics at different frequency. Two obvious
dielectric abnormal peaks are obtained for all samples. The peak around 200 °C is the
transition temperature To-t of orthorhombic to tetragonal and the other is the Curie
Unpoled and
aged
KNN-0.01Mn-air
Poled and aged
KNN-0.01Mn-air
Poled and aged
KNN-0.01Mn-Ar
Poled and
aged
KNN-Ar
1
kHz
To-t 183 183 175 205
Tc 413 413 410 424
r at 25 °C 268 284 262 525
tan
at
25 °C
0.0114 0.0193 0.0129 0.061
10
kHz
To-t 183 183 175 205
Tc 413 413 410 424
r at 25 °C 263 276 257 496
tan
at
25 °C
0.0123 0.0201 0.0126 0.51
100
kHz
To-t 183 183 175 205
Tc 413 413 410 424
r at 25 °C 258 267 251 461
tan
at
25 °C
0.0155 0.0213 0.0125 0.054
temperature Tc. These two peaks do not shift with increasing the frequency. However,
the intensities of the peaks for εr and tanδ at Tc decrease obviously with rising
frequency from 1 kHz to 100 kHz. Table S1 lists the dielectric properties of the
KNN-xMn ceramics. With addition of MnO2, the To-t, Tc, tanδ and εr decrease. This
kind of behavior is similar with the results reported by other researches for Mn-doped
KNN system.1,2 The T
o-t and Tc of KNN-0.01Mn-Ar slightly shift to lower
temperature than that of KNN-0.01Mn-air.
Reference
1W. J Wu, M. Chen, Y. C. Ding, C. Q. Liu, J. Alloy Compd. 588, 496 (2014).
2F. Rubio-Marcos,P. Marchet, X. Vendrell, J. J. Romero, F. Remondiere, L. Mestres, J.
F. Fernandez, J. Alloy Compd. 509, 8804 (2011).
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Article
Mn2+-doped (K,Na,Li)(Nb,Ta,Sb)O3 lead-free piezoelectric ceramics have been prepared by a conventional sintering technique. The effects of Mn2+ doping on the phase structure, microstructure and ferro-piezoelectric properties of the ceramics have been evaluated. MnO doping modifies the (K,Na,Li)(Nb,Ta,Sb)O3 structure, giving rise to the appearance of a TTB-like secondary phase and to changes on the orthorhombic to tetragonal phase transition temperature. The modification of this temperature induces a reduction of the piezoelectric constants, which is accompanied by an increase on the mechanical quality factor. Mn2+ ions incorporate into the perovskite structure in different off ways depending on their concentration.
  • W Wu
  • M Chen
  • Y C Ding
  • C Q Liu
W. J Wu, M. Chen, Y. C. Ding, C. Q. Liu, J. Alloy Compd. 588, 496 (2014).