NSF/EPRSC joint proposal on the effect of constraint and thickness on octahedral tilt transitions in perovskite structured thin films

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering

Abstract

This proposal aims to investigate a range of perovskite structured thin films using a combination of Raman spectroscopy, in-situ transmission electron microscopy and synchrotron X-radiation in order to determine how constraint controls the onset and temperature dependence of octahedral tilt transitions in thin films and ensuing domain structure. It is anticpated that this will give a greater understanding of how constraint influences functional properties in ferroelectric and dielectric thin layers. The proposal will concentrate on three key systems in which tilt transitions are known to influence macroscopic properties; PbZrxTi(1-x)O3, Ag(Nb,Ta)O3 and the newly discovered (1-x)BiMeO3-xPbTiO3 solid solutions. The proposal is joint between University of Sheffield, Pennsylvania State University and Argonne National Laboratory. The latter will submit an independent National Science Foundation proposal which directly compliments the work proposed here. The programme is for 4 years at the request of the National Science Foundation, USA.

Publications

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Bintachitt P (2010) Collective dynamics underpins Rayleigh behavior in disordered polycrystalline ferroelectrics. in Proceedings of the National Academy of Sciences of the United States of America

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Dechakupt T (2008) Chemical Solution-Deposited BaTiO 3 Thin Films on Ni Foils: Microstructure and Interfaces in Journal of the American Ceramic Society

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Han Y (2010) Structural phase transitions in AgTa0.5Nb0.5O3 thin films in Journal of Applied Physics

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Han Y (2009) (111)(p) microtwinning in SrRuO(3) thin films on (001)(p) LaAlO(3). in Acta crystallographica. Section B, Structural science

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Johnson-Wilke R (2013) Coherently strained epitaxial Pb(Zr 1-x Ti x )O 3 thin films in Journal of Applied Physics

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Khan H (2010) Phase transitions in LixAg1-x(Nb0.5Ta0.5)O3 solid solutions in Journal of Applied Physics

 
Description The project was intentionally fundamental in nature and focused on understanding the role of substrate induced strain in ferroelectric thin films on the onset temperature of octahedral tilt transitions. The main fundamental findings were:

1) In relaxed PZT films, the region above the nominal octahedral transition temperature was composed of short range ordered rather than zero amplitude tilting. This has led to a radical rethink of the nature of octahedral tilt transitions in perovskites, a major issue for a wide number of functional ceramics.

2) Strain could be used to increase the onset temperature of the ferroelectric but decreased that of the octahedral transition in PZT. This gives an interesting compositional/strain design window for tilted ferroelectric materials such as PZT in thin films since unwanted modulations in polarisation due to the onset of tilting can be designed out of the film.
Exploitation Route No direct non academic impact but strained PZT films may be used in commercial applications in the future and this work has aided in their potential development. Fundamental science not suited to commercial or societal exploitation
Sectors Aerospace, Defence and Marine,Electronics

 
Description The findings from this project have been presented at a number of major international conferences and have been the subject of a number of key refereed articles in major international journals. The critical results illustrated the manner in which tilt transitions in perovskite thin films can be affected by strain. A new theory of tilt transition behaviour was proposed as a result of this work which demonstrated that the onset temperature of the tilt transition in the PZT phase diagram is in fact the point that the tilting locks into the pre-existing ferroelectric domain structure.
First Year Of Impact 2011
Sector Aerospace, Defence and Marine,Electronics
Impact Types Societal

 
Description Centre for Dielectrics and Piezoelectrics (CDP 
Organisation Center for Dielectrics & Piezoelectrics
PI Contribution Centre for Dielectrics and Piezoelectrics (CDP). Sheffield has now been voted in as an Affiliate Partner in the NSF funded CDP alongside North Carolina State University (NCSU) and Pennsylvania State University (PSU. The CDP has ~25 members which include Samsung, Apple, Murata and 3M. The joint grant with PSU was instrumental in cement our relationship with the centre based on a number of high profile publications with the CDP co-director Susan Mckinstry (international CoI on grant)
Collaborator Contribution Susan McKinstry and Ian M. Reaney are now co-directors of the CDP. The publications helped demontrate to the Industrial Members the strength of the partnership between the CDP and Sheffield
Impact Multidisciplinary. Ceramic Engineering, Life Cycle Assessment, Materials Modelling. Has led to joint projects, research, secondments and industrial funding
Start Year 2017
 
Description Conferences (international) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The research formed the basis of numerous talks given by either my researcher, myself or my collaborator. The highlight was a joint presentation by Professor Mckinstry (CoI) at at a local structure symposium at the International Conference on Electroceramics in Osaka, Japan in 2010
Year(s) Of Engagement Activity 2008,2009,2010