In this work, the antiferroelectric-ferroelectric phase switching behavior of Pb0.99Nb0.02[(Zr0.57Sn0.43)1-yTiy]0.98O3 (PNZST 43/100y/2) with compositions near the
tetragonal antiferroelectric / rhombohedral ferroelectric phase boundary (y = 0.060~0.075) were characterized.
Ceramics with compositions far from the phase boundary (e.g. y = 0.060) underwent a reversible field-forced antiferroelectric ↔ ferroelectric phase transformation and could find use in energy storage devices or digital transducers (due to the on/off states encoded in the strain accompanying the transformation). The ceramic with composition y = 0.075 underwent an irreversible field-assisted antiferroelectric → ferroelectric phase transformation after which the ferroelectric phase was stable with subsequent electric field cycling. Ceramics with intermediate Ti contents exhibited mixed antiferroelectric/ferroelectric character after multiple electric field cycles. Those with compositions y = 0.069 and 0.071 retained a significant percentage of the strain of the induced ferroelectric phase after complete field removal; this strain could be recovered with a small reverse bias. This suggested that the ferroelectric phase was metastable after field removal and electric fields with reversed polarity could trigger a ferroelectric-to-antiferroelectric phase transformation. Investigation with in-situ XRD confirmed the electric field-induced ferroelectric-to- antiferroelectric phase transformation in PNZST 43/7.1/2 ceramics.
This discovery may lead to new electric energy storage devices. Typically, energy stored in capacitors utilizing antiferroelectric materials makes use of a field-forced phase transformation, which requires that a voltage be maintained to prevent the reverse
transformation and subsequent energy discharge. The key advantage offered by compositions reported here is the ability to store energy in the metastable ferroelectric phase without the need to maintain a voltage. On demand, the stored energy can be released upon application of a minor electric field with reversed polarity. Before such devices can be put into use, several key questions must be answered. First, the longevity of the metastable ferroelectric phase at zero field should be evaluated to ensure any electrical energy stored in ferroelectric phase is not lost if the ceramic slowly reverts to the non-polar antiferroelectric phase as it ages. A previous study by He and Tan [34] investigated the time-induced reverse transition at room temperature from the metastable ferroelectric phase in PNZST 43/7/2. It was found that the time-scale is on the order of hours; 150 hours after the phase was induced, the reemergence of the antiferroelectric phase was detected by Raman spectroscopy. However, it should be noted that the hysteresis loop of their PNZST 43/7/2 sample appeared to possess a significant antiferroelectric distortion; the PNZST 43/7.1/2 samples studied herein comparatively possessed stronger ferroelectric ordering, and would thus likely be less susceptible to detrimental ageing effects.
Another critical issue that warrants in-depth investigation is how repeated antiferroelectric ↔ ferroelectric phase switching impacts the operation, performance, and failure of energy storage capacitors. Specifically, since this phase transformation involves a volume change on the order of ~0.5% and a phase transformation takes places in each charge or discharge cycle, internal mechanical stresses will arise during operation in ceramics with randomly oriented grains. The evolution and the impact of these internal stresses in
antiferroelectric ceramics when subjected to high electric fields will play a vital role in the viability for use in reliable energy storage devices.
In this study the induced ferroelectric phase was further characterized at high fields in composition y = 0.060. It was discovered that the induced ferroelectric phase exhibits auxetic behavior under electrical loads, i.e. expansion in the transverse direction while being stretched longitudinally. This behavior is strikingly different from normal ferroelectrics, such as PZT, which always contract in the transverse direction when stretched by uniaxial electric fields. This result suggests that there may be a special signature carried with the induced ferroelectric phase from its parent antiferroelectric phase that results in the unexpected auxetic behavior, which could be caused by a straightening of the tilted oxygen octahedra of the perovskite structure. Observation of the domain structure by TEM at high fields (E >> EF) in PNZST 43/6.0/2 as compared with a regular ferroelectric phase (e.g.
rhombohedral PZT) may provide visual evidence to support this speculation.
Additionally, the impact of radial confinement on phase switching in PNZST 43/6.0/2 ceramics was also investigated. Axial compressive pre-stresses applied prior to electric field loading were found to delay the electric field-induced antiferroelectric-to-ferroelectric phase transformation. Radial compressive pre-stresses, on the other hand, progressively suppressed the phase transformation. The difference in behavior can be rationalized by considering the effects each compressive stress configuration has on ferroelastic domain switching in the antiferroelectric state prior to the phase transformation.
References
1. G.H. Haertling, "Ferroelectric ceramics: History and technology," Journal of the
American Ceramic Society, 82, 797-818 (1999).
2. A.J. Moulson and J.M. Herbert, "Electroceramics: Materials, properties, applications," 2nd ed. West Sussex ; New York: Wiley. 2003.
3. R.E. Newnham, "Properties of materials: Anisotropy, symmetry, structure." Oxford ; New York: Oxford University Press. 2005.
4. M.E. Lines and A.M. Glass, "Principles and applications of ferroelectrics and related materials." Oxford: Clarendon Press. 1977.
5. T. Mitsui, I. Tatsuzaki, and E. Nakamura, "An introduction to the physics of ferroelectrics." New York: Gordon and Breach Science Publishers. 1976.
6. J.Y. Li and D. Liu, "On ferroelectric crystals with engineered domain configurations,"
Journal of the Mechanics and Physics of Solids, 52, 1719-42 (2004).
7. B.A. Strukov and A.P. Levanyuk, "Ferroelectric phenomena in crystals: Physical foundations." Berlin ; New York: Springer. 1998.
8. K. Uchino, "Piezoelectric actuators and ultrasonic motors." Boston: Kluwer Academic Publishers. 1997.
9. X. Zhao, et al., "Electric field-induced phase transitions in (111)-, (110)-, and (100)- oriented Pb(Mg1/3Nb2/3)O3 single crystals," Physical Review B, 75, 104106/1-12
(2007).
10. R.E. Cohen, "Origin of ferroelectricity in perovskite oxides," Nature, 358, 136-38 (1992).
11. D. Damjanovic, "Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics," Reports on Progress in Physics, 61, 1267-324 (1998). 12. G.W. Taylor, "Electrical properties of niobium-doped ferroelectric Pb(Zr, Sn, Ti)O3
ceramics," Journal of Applied Physics, 38, 4697-706 (1967).
13. X. Tan, et al., "Effect of uniaxial stress on ferroelectric behavior of (Bi1/2Na1/2)TiO3-
based lead-free piezoelectric ceramics," Journal of Applied Physics, 106, 044107/1-7 (2009).
14. J. Rodel, et al., "Perspective on the development of lead-free piezoceramics," Journal
15. A.B.K. Njiwa, et al., "Influence of radial stress on the poling behaviour of lead zirconate titanate ceramics," Acta Materialia, 55, 675-80 (2007).
16. B. Jaffe, W.R. Cook, and H.L. Jaffe, "Piezoelectric ceramics." London ; New York: Academic Press. 1971.
17. B. Noheda, et al., "A monoclinic ferroelectric phase in the Pb(Zr1-xTix)O3 solid
solution," Applied Physics Letters, 74, 2059-61 (1999).
18. R. Guo, et al., "Origin of the high piezoelectric response in PbZr1-xTixO3," Physical
Review Letters, 84, 5423-26 (2000).
19. L. Bellaiche, A. Garcia, and D. Vanderbilt, "Finite-temperature properties of Pb(Zr1- xTix)O3 alloys from first principles," Physical Review Letters, 84, 5427-30 (2000).
20. C. Kittel, "Theory of antiferroelectric crystals," Physical Review, 82, 729-32 (1951). 21. L.E. Cross, "Antiferroelectric-ferroelectric switching in a simple Kittel
antiferroelectric," Journal of the Physical Society of Japan, 23, 77-82 (1967).
22. K. Uchino, et al., "Electrostrictive effects in antiferroelectric perovskites," Journal of
Applied Physics, 52, 1455-59 (1981).
23. Y.L. Wang, et al., "Phase transition study of PZT 95/5 ceramics," Physica B & C, 150, 168-74 (1988).
24. D. Berlincourt, B. Jaffe, and H.H.A. Krueger, "Stability of phases in modified lead zirconate with variation in pressure electric field temperature and composition,"
Journal of Physics and Chemistry of Solids, 25, 659-74 (1964).
25. B.A. Scott and G. Burns, "Crystal growth and observation of the ferroelectric phase of PbZrO3," Journal of the American Ceramic Society, 55, 331-33 (1972).
26. E. Sawaguchi, "Ferroelectricity versus antiferroelectricity in the solid solutions of PbZrO3 and PbTiO3," Journal of the Physical Society of Japan, 8, 615-29 (1953).
27. Y.J. Feng, Z. Xu, and X. Yao, "Effect of Sn doping on the phase transition behaviors of antiferroelectric lead zirconate titanate," Materials Science and Engineering B-
Solid State Materials for Advanced Technology, 99, 499-501 (2003).
28. W.Y. Pan, et al., "Large displacement transducers based on electric field forced phase transitions in the tetragonal (Pb0.97la0.02)(Ti,Zr,Sn)O3 family of ceramics," Journal of
Applied Physics, 66, 6014-23 (1989).
29. K. Uchino, "Digital displacement transducer using antiferroelectrics," Japanese
30. K.Y. Oh, et al., "Piezoelectricity in the field-induced ferroelectric phase of lead zirconate-based antiferroelectrics," Journal of the American Ceramic Society, 75, 795-99 (1992).
31. A. Pelaiz-Barranco and D.A. Hall, "Influence of composition and pressure on the electric field-induced antiferroelectric to ferroelectric phase transformation in lanthanum modified lead zirconate titanate ceramics," IEEE Transactions on
Ultrasonics Ferroelectrics and Frequency Control, 56, 1785-91 (2009).
32. H. Tang, et al., "Effect of Nb doping on microstructure and electric properties of lead zirconate stannum titanate antiferroelectric ceramics," Journal of Materials Research, 24, 1642-45 (2009).
33. P. Yang, "Electrically induced antiferroelectric-ferroelectric phase transformations in lead-zirconate titanate stannate ceramics," PhD Thesis. University of Illinois, Urbana-Champaign, 1992.
34. H. He and X. Tan, "Raman spectroscopy study of the phase transitions in Pb0.99Nb0.02[(Zr0.57Sn0.43)(1-y)Tiy](0.98)O3 ceramics," Journal of Physics-Condensed
Matter, 19, 136003/1-13 (2007).
35. D. Forst, "Structure-property relationships and phase stability in the tin-modified lead zirconate titanate crystalline solution series," PhD Thesis. University of Illinois, Urbana-Champaign, 1996.
36. Y.W. Nam and K.H. Yoon, "Effect of PbO content on dielectric and electric field induced strain properties in Y-modified lead zirconate titanate stannate," Materials
Research Bulletin, 33, 331-39 (1998).
37. K. Uchino, "Ferroelectric devices." New York: Marcel Dekker. 2000.
38. C.V. Raman and T.M.K. Nedungadi, "The α-β transformation of quartz," Nature, 145, 147-47 (1940).
39. W. Cochran, "Crystal stability and the theory of ferroelectricity," Physical Review
Letters, 3, 412-14 (1959).
40. W. Cochran, "Crystal stability and the theory of ferroelectricity," Advances in
Physics, 9, 387-423 (1960).
41. P.W. Anderson. In: Fizika Dielektrikov (Physics of Dielectrics), (G.I. Skanavi, ed.). Akad. Nauk. SSSR (Academy of Sciences of the USSR), Moscow, 1960.
42. R. Blinc, "The soft mode in H-bonded ferroelectrics revisited," Croatica Chemica
43. G.A. Samara, T. Sakudo, and K. Yoshimitsu, "Important generalization concerning the role of competing forces in displacive phase transitions," Physical Review Letters, 35, 1767-69 (1975).
44. P. Yang and D.A. Payne, "The effect of external field symmetry on the antiferroelectric-ferroelectric phase transformation," Journal of Applied Physics, 80, 4001-05 (1996).
45. W. Pan, et al., "Field-forced antiferroelectric-to-ferroelectric switching in modified lead zirconate titanate stannate ceramics," Journal of the American Ceramic Society, 72, 571-78 (1989).
46. M. Avdeev, et al., "Pressure-induced ferroelectric to antiferroelectric phase transition in Pb0.99(Zr0.95Ti0.05)(0.08)Nb0.2O3," Physical Review B, 73, 064105/1-14 (2006).
47. D.H. Zeuch, S.T. Montgomery, and D.J. Holcomb, "Uniaxial compression experiments on lead zirconate titanate 95/5-2Nb ceramic: Evidence for an orientation- dependent, "maximum compressive stress" criterion for onset of the ferroelectric to antiferroelectric polymorphic transformation," Journal of Materials Research, 15, 689-703 (2000).
48. S.E. Park, et al., "Electric field induced phase transition of antiferroelectric lead lanthanum zirconate titanate stannate ceramics," Journal of Applied Physics, 82, 1798-803 (1997).
49. D. Berlincourt, "Transducers using forced transitions between ferroelectric and antiferroelectric states," IEEE Transactions on Sonics and Ultrasonics, su-13, 116-24 (1966).
50. P. Yang and D.A. Payne, "Thermal stability of field-forced and field-assisted antiferroelectric-ferroelectric phase transformations in Pb(Zr,Sn,Ti)O3," Journal of
Applied Physics, 71, 1361-67 (1992).
51. H. He and X. Tan, "Electric-field-induced transformation of incommensurate modulations in antiferroelectric Pb0.99Nb0.02[(Zr1-xSnx)(1-y)Tiy](0.98)O3," Physical
Review B, 72, 024102/1-10 (2005).
52. H. He and X. Tan, "A comparative study of the structure and properties of Sn- modified lead zirconate titanate ferroelectric and antiferroelectric ceramics," Journal
of the American Ceramic Society, 90, 2090-94 (2007).
53. Y.J. Feng, et al., "Phase transition characters in tin modified lead zirconate titanate compounds," Ferroelectrics, 358, 894-98 (2007).
54. D. Damjanovic, T.R. Gururaja, and L.E. Cross, "Anisotropy in piezoelectric properties of modified lead titanate ceramics," American Ceramic Society Bulletin, 66, 699-703 (1987).
55. A. Yeganeh-Haeri, D.J. Weidner, and J.B. Parise, "Elasticity of α-cristobalite: A silicon dioxide with a negative Poisson's ratio," Science, 257, 650-52 (1992).
56. N.R. Keskar and J.R. Chelikowsky, "Negative Poisson ratios in crystalline SiO2 from
first-principles calculations," Nature, 358, 222-24 (1992).
57. D.L. Corker, et al., "A neutron diffraction investigation into the rhombohedral phases of the perovskite series PbZr1-xTixO3," Journal of Physics-Condensed Matter, 10,
6251-69 (1998).
58. C.T. Blue, et al., "In situ X-ray diffraction study of the antiferroelectric-ferroelectric phase transition in PLSnZT," Applied Physics Letters, 68, 2942-44 (1996).
59. H.C. Cao and A.G. Evans, "Nonlinear deformation of ferroelectric ceramics," Journal
of the American Ceramic Society, 76, 890-96 (1993).
60. D.A. Hall, et al., "In-situ neutron diffraction study of the rhombohedral to orthorhombic phase transformation in lead zirconate titanate ceramics produced by uniaxial compression," Philosophical Magazine Letters, 87, 41-52 (2007).
61. X. Tan, et al., "Electric-field-induced antiferroelectric to ferroelectric phase transition in mechanically confined Pb0.99Nb0.02[(Zr0.57Sn0.43)(0.94)Ti0.06](0.98)O3," Physical Review
Acknowledgements
First and foremost I wish to express gratitude toward my committee members, Dr. Scott Beckman and Dr. Wei Hong, and my major professor, Dr. Xiaoli Tan, whose respectful guidance, patience, encouragement, and support allowed me to complete this study and gain confidence in myself as a researcher along the way. I also wish to thank my current and former group members Xiaohui Zhao, Weiguo Qu, Cheng Ma, Wei Hu, Orawan Khamman, and Emily Decker for their perpetual willingness to offer assistance and advice.
Much of this research was made possible by the financial support and collaborative efforts provided by Professor Jürgen Rödel to fund my work at the Technische Universität Darmstadt. It was there I had the pleasure of working with some of the most endearing colleagues I have ever collaborated with. Though I made too many friends to list here individually, I wish to say ‘thanks’ for all they did for me. Deserving of special recognition are Professor Torsten Granzow, Professor Wook Jo, Professor Kyle Webber, Emil Aulbach, and Mie Marsilius for their mentorship and aid with measurements and analysis.
On several occasions I relied upon the modification and construction of devices, and for that I wish to thank Kevin Brownfield for his machining expertise. The in-situ XRD work would not have been completed as efficiently without the help I received from Scott Schlorholtz, whose suggestions helped facilitate the study.
Lastly, I wish to acknowledge the monumental role played by my friends and family, especially my parents, Beth and Frank Frederick, in helping me achieve success as a graduate student. None of my accomplishments would have been possible without their unconditional love and understanding, and for that I am forever indebted to them. Thank you.