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Title: Electric field-induced phase transitions in Li-modified Na[subscript 0.5]K[subscript 0.5]NbO[subscript 3] at the polymorphic phase boundary

Authors:
; ; ; ; ;  [1];  [2];  [2];  [2]
  1. (Suranaree)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
U.S. ARMY RESEARCHFOREIGN
OSTI Identifier:
1168513
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Appl. Phys.; Journal Volume: 117; Journal Issue: (2) ; 01, 2015
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Iamsasri, Thanakorn, Tutuncu, Goknur, Uthaisar, Chunmanus, Wongsaenmai, Supattra, Pojprapai, Soodkhet, Jones, Jacob L., NCSU), Maejo), and Florida). Electric field-induced phase transitions in Li-modified Na[subscript 0.5]K[subscript 0.5]NbO[subscript 3] at the polymorphic phase boundary. United States: N. p., 2016. Web. doi:10.1063/1.4905613.
Iamsasri, Thanakorn, Tutuncu, Goknur, Uthaisar, Chunmanus, Wongsaenmai, Supattra, Pojprapai, Soodkhet, Jones, Jacob L., NCSU), Maejo), & Florida). Electric field-induced phase transitions in Li-modified Na[subscript 0.5]K[subscript 0.5]NbO[subscript 3] at the polymorphic phase boundary. United States. doi:10.1063/1.4905613.
Iamsasri, Thanakorn, Tutuncu, Goknur, Uthaisar, Chunmanus, Wongsaenmai, Supattra, Pojprapai, Soodkhet, Jones, Jacob L., NCSU), Maejo), and Florida). Fri . "Electric field-induced phase transitions in Li-modified Na[subscript 0.5]K[subscript 0.5]NbO[subscript 3] at the polymorphic phase boundary". United States. doi:10.1063/1.4905613.
@article{osti_1168513,
title = {Electric field-induced phase transitions in Li-modified Na[subscript 0.5]K[subscript 0.5]NbO[subscript 3] at the polymorphic phase boundary},
author = {Iamsasri, Thanakorn and Tutuncu, Goknur and Uthaisar, Chunmanus and Wongsaenmai, Supattra and Pojprapai, Soodkhet and Jones, Jacob L. and NCSU) and Maejo) and Florida)},
abstractNote = {},
doi = {10.1063/1.4905613},
journal = {J. Appl. Phys.},
number = (2) ; 01, 2015,
volume = 117,
place = {United States},
year = {Fri Sep 23 00:00:00 EDT 2016},
month = {Fri Sep 23 00:00:00 EDT 2016}
}
  • The electric field-induced phase transitions in Li-modified Na{sub 0.5}K{sub 0.5}NbO{sub 3} at the polymorphic phase boundary (PPB) were observed using in situ X-ray diffraction. The ratio of monoclinic to tetragonal phase fraction was used as an indicator of the extent and reversibility of the phase transitions. The reversibility of the phase transition was greater in compositions further from the PPB. These results demonstrate that the field-induced phase transition is one of the origins of high piezoelectric properties in lead-free ferroelectric materials.
  • Structure and phase transitions of (1-y)((1-x)Bi 1/2Na 1/2TiO 3-xBi 1/2K 1/2TiO 3)-yK 0.5Na 0.5NbO 3 (x; y) piezoceramics (0.1 ≤ x ≤ 0.4; 0 ≤ y ≤ 0.05) were investigated by transmission electron microscopy, neutron diffraction, temperature-dependent x-ray diffraction, and Raman spectroscopy. The local crystallographic structure at room temperature (RT) does not change by adding K 0.5Na 0.5NbO 3 to Bi 1/2Na 1/2TiO 3-xBi 1/2K 1/2TiO 3 for x = 0.2 and 0.4. The average crystal structure and microstructure on the other hand develop from mainly long-range polar order with ferroelectric domains to short-range order with polar nanoregions displaying amore » more pronounced relaxor character. The (0.1; 0) and (0.1; 0.02) compositions exhibit monoclinic Cc space group symmetry, which transform into Cc + P4bm at 185 and 130 °C, respectively. This high temperature phase is stable at RT for the morphotropic phase boundary compositions of (0.1; 0.05) and all compositions with x = 0.2. For the compositions of (0.1; 0) and (0.1; 0.02), local structural changes on heating are evidenced by Raman; for all other compositions, changes in the long-range average crystal structure were observed.« less
  • Lead-free, potassium sodium niobate piezoelectric ceramics substituted with lithium (K{sub 0.5-x/2},Na{sub 0.5-x/2},Li{sub x})NbO{sub 3} or lithium and tantalum (K{sub 0.5-x/2},Na{sub 0.5-x/2},Li{sub x})(Nb{sub 1-y},Ta{sub y})O{sub 3} have been synthesized by traditional solid state sintering. The compositions chosen are among those recently reported to show high piezoelectric properties [Y. Saito, H. Takao, T. Tani, T. Nonoyama, K. Takatori, T. Homma, T. Nagaya, and M. Nakamura, Nature (London) 42, 84 (2004); Y. Guo, K. Kakimoto, and H. Ohsato, Appl. Phys. Lett. 85, 4121 (2004); Mater. Lett. 59, 241 (2005)]. We show that high densities and piezoelectric properties can be obtained for all compositionsmore » by pressureless sintering in air, without cold isostatic pressing, and without any sintering aid or special powder treatment. Resonance and converse piezoelectric (strain-field) measurements show a thickness coupling coefficient k{sub t} of 53% and converse piezoelectric coefficient d{sub 33} around 200 pm/V for the Li-substituted ceramics, and a k{sub t} of 52% and d{sub 33} over 300 pm/V for the Li- and Ta-modified samples. The unipolar strain-field hysteresis is small and comparable to that measured under similar conditions in hard Pb(Zr,Ti)O{sub 3}. A peak of piezoelectric properties can be noted close to the morphotropic phase boundary. These ceramics look very promising as possible, practicable, lead-free replacements for lead zirconate titanate.« less
  • The mechanism of the giant unipolar strain recently observed in a lead-free piezoceramic, 0.92(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.06BaTiO{sub 3}-0.02(K{sub 0.5}Na{sub 0.5})NbO{sub 3}[S.-T. Zhang, A. B. Kounga, E. Aulbach, H. Ehrenberg, and J. Roedel, Appl. Phys. Lett. 91, 112906 (2007) was investigated. The validity of the previously proposed mechanism that the high strain comes both from a significant volume change during the field-induced phase transition, from an antiferroelectric to a ferroelectric phase and the domain contribution from the induced ferroelectric phase was examined. Monitoring the volume changes from the simultaneously measured longitudinal and transverse strains on disk-shaped samples showed that the phasemore » transition in this specific material does not involve any notable volume change, which indicates that there is little contribution from a volume change due to the phase transition to the total strain response. Temperature dependent hysteresis measurements on unpoled samples of a nearby ferroelectric composition, 0.93(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.06BaTiO{sub 3}-0.01(K{sub 0.5}Na{sub 0.5})NbO{sub 3} demonstrated that the origin of the large strain is due to the presence of a nonpolar phase that brings the system back to its unpoled state once the applied electric field is removed, which leads to a large unipolar strain.« less