High electromechanical response in the non morphotropic phase boundary piezoelectric system PbTiO3-Bi(Zr1/2Ni1/2)O-3

Pandey, Rishikesh and Narayan, Bastola and Khatua, Dipak Kumar and Tyagi, Shekhar and Mostaed, Ali and Abebe, Mulualem and Sathe, Vasant and Reaney, Ian M. and Ranjan, Rajeev (2018) High electromechanical response in the non morphotropic phase boundary piezoelectric system PbTiO3-Bi(Zr1/2Ni1/2)O-3. In: PHYSICAL REVIEW B, 97 (22).

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Abstract

There is a general perception that a large piezoelectric response in ferroelectric solid solutions requires a morphotropic/polymorphic phase boundary (MPB/PPB), i.e., a composition driven interferroelectric instability. This correlation has received theoretical support from models which emphasize field driven polarization rotation and/or interferroelectric transformations. Here, we show that the ferroelectric system (1 - x)PbTiO3-(x)Bi(Zr1/2Ni1/2)O-3 (PT-BNZ), which shows d(33)(similar to 400 pC/N) comparable to the conventional MPB/PPB systems, does not belong to this category. In the unpoled state the compositions of PT-BNZ showing large d(33) exhibit a coexistence of tetragonal and cubiclike (CL) phases on the global length scale. A careful examination of the domain strucures and global structures (both in the unpoled and poled states) revealed that the CL phase has no symptom of average rhombohedral distortion even on the local scale. The CL phase is rather a manifestation of tetragonal regions of short coherence length. Poling increases the coherence length irreversibly which manifests as poling induced CL -> P4mm transformation on the global scale. PT-BNZ is therefore qualitatively different from the conventional MPB piezoelectrics. In the absence of the composition and temperature driven interferroelectric instability in this system, polarization rotation and interferroelectric transformation are no longer plausible mechanisms to explain the large electromechanical response. The large piezoelectricity is rather associated with the increased structural-polar heterogeneity due to domain miniaturization without the system undergoing a symmetry change. Our study proves that attainment of large piezoelectricity does not necessarily require interferroelectric instability (and hence morphotropic/polymorphic phase boundary) as a criterion.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW B
Publisher:	AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Additional Information:	Copyright of this article belong to AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	19 Jul 2018 14:54
Last Modified:	19 Jul 2018 14:54
URI:	http://eprints.iisc.ac.in/id/eprint/60241

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