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A Crystal-chemical Framework for Relaxor versus Normal Ferroelectric
Behavior in Tetragonal Tungsten Bronzes
X. Zhu1, M. Fu2, M. C. Stennett3, P. M. Vilarinho4, I. Levin5, C.A. Randall6
J. Gardner7, F.D. Morrison,7 and I. M. Reaney3
1
Department of Materials Science and Engineering,
Zhejiang University, Hangzhou, China.
2
Shanxi Materials Analysis and Research Center,
School of Materials Science and Engineering,
Northwestern Polytechnical University,
Xi’an 710000, China.
3
Department of Materials Science and Engineering
University of Sheffield, Sheffield, S1 3JD, UK
4
Department of Materials and Ceramic Engineering
Center for Research in Ceramics and Composite Materials,
CICECO, University of Aveiro, 3810–193 Aveiro, Pt.
5
Materials Measurement Science Division,
National Institute of Standards and Technology,
Gaithersburg MD 20899, USA
6
Center for Dielectrics and Piezoelectrics
Materials Research Institute, Millennium Science Complex
The Pennsylvania State University, University Park, PA 16802, USA
7
School of Chemistry, University of St Andrews,
St Andrews, KY16 9ST, UK.
*e-mail: I.M.Reaney@sheffield.ac.uk
Tetragonal Tungsten Bronzes (TTBs) - an important class of oxides known to exhibit ferroelectricity undergo complex distortions, including rotations of oxygen octahedra, which give rise to either
incommensurately or commensurately modulated superstructures. Many TTBs display broad, frequencydependent relaxor dielectric behaviour rather than sharper frequency-independent normal ferroelectric
anomalies but the exact reasons that favor a particular type of dielectric response for a given composition
remain unclear. In this contribution the influence of incommensurate/commensurate displacive modulations
on the onset of relaxor/ferroelectric behaviour in TTBs is assessed in the context of basic crystal-chemical
factors, such as positional disorder, ionic radii and polarizabilities, and point defects. We present a predictive
crystal-chemical model that rationalizes composition-structure-properties relations for a broad range of TTB
systems.
CV Professor Ian M Reaney
BSc MSc PhD MInstP CPhys CEng FRMS
Professor in Functional Ceramics
Faculty of Engineering
Department of Materials Science and Engineering
Sir Robert Hadfield Building, Mappin Street
Sheffield, S1 3JD
Telephone: +44 (0) 114 222 5471
Email: i.m.reaney@sheffield.ac.uk
https://www.shef.ac.uk/materials/staff/imreaney01
Building upon international recognition for his pioneering research in microwave, piezoelectric
materials and thin films (over 300 scientific papers, 19 of which have over 100 citations), for the
last few of years Ian has applied his leadership to research into novel industrial processes and
products, developing strong industrial collaborations with device manufacturers (notably
Powerwave Technologies Inc, Sarantel Ltd, GE Thermometrics and Ilika Technologies) leading to
industrial patents, new contracts and new products in the field of sensors, actuators and antennas.
Ian is the Deputy Head of the Department of Materials Science and Engineering where he is also
the Director of Teaching and Learning and Examinations Officer. He was awarded a Personal Chair
at University of Sheffield in 2007 but joined the Faculty of Engineering in 1994, initially as a
PDRA, then as a Lecturer from 1995. He obtained his PhD from the University of Manchester in
1989 and worked as post-doctoral researcher at the University of Essex before joining the
Laboratoire de Ceramique, Ecole Polytechnique Federale de Lausanne in Switzerland in 1991.
Research Leadership
Ian has been awarded over £20M in career income for engineering research, over £1.5M of which
has been industrially related; he has been Principal or Co-Investigator on 27 EPSRC awards. His
scientific achievements have arisen from the successful delivery of a wide portfolio of large
projects, with a research group of over 15 researchers for the last 15 years. During this time he has
supervised to completion over 40 PhD & MSc students. His publications, over 300 scientific
papers, receive ~900 citations per year; many of these have announced major breakthroughs in
scientific understanding with 19 papers having over 100 citations. His career H-index = 45 (H5 =
31 (Googlescholar). His research leadership in a wide range of functional ceramic disciplines has
been recognized by >60 Invited/Plenary talks at International Conferences on topics such as MW
ceramics, bioceramics, relaxor-ferroectrics and piezoelectrics. Recently, he gave an invited lecture
recent to a multidisciplinary audience on ‘Failure, The Greatest Teacher’ at Electronic Materials
and their Applications in 2015.
Industrial Collaboration
Ian’s personal research is in the development of microwave and piezoelectric materials for
manufacture of electronic devices, principally concerned with sensor, actuator and antenna
applications. He has also published leading papers on functional glasses (see 10 most cited papers).
In the last few years he has established strong working relations with a number of UK based
companies such as Filtronic plc (collaborating on novel filters with the UK operations of this global
leader in wireless communications), Sarantel Ltd (collaborating in novel device concepts and
materials for this UK manufacturer who led globally in the design of miniature GPS antennas),
Morgan Electroceramics (collaborating on their manufacture of piezoelectric and dielectric
materials for devices such as transducers, sensors and actuators), GE Thermometrics (collaborating
on their development of novel thermal sensors for the UK operations of GE Group’s “Measurement
& Control business), Ilika plc (consultancy and development of novel processes for ceramics
manufacture). Ian’s research leadership and personal expertise have resulted in these companies
securing patents (including piezoelectric/microwave ceramics and multilayer metallisations) and
developing several new electronic device products.
Illustrative Research Projects
• Principal Investigator on ‘Substitution and Sustainability in Functional Materials and
Devices’, EP/L017563/1, £2.44M.
• Principal Investigator on EP/I038934/1 on ‘Defect Domain Wall Interactions in
Ferroelectric Thin Films’ with Susan McKinstry, Pennsylvania State University, USA and
Sergei Kalinnin Oak Ridge National Laboratories, USA, £393k.
•
•
•
Principal Investigator on EP/F006098/1, Nanostructure in Functional Ceramics, £607k.
Co-Investigator on Programme Grant ‘New and Improved Electroceramics’
EP/G005001/1, £3.8M.
Knowledge Transfer Partnerships: Ilika technologies Ltd (£350k), Sarantel Ltd (£550k).
Dyesol UK Ltd (£215k)
National and International Recognition
• Adjunct Professor at Pennsylvania State University, USA.
• Visiting Professor, University of Aveiro, Portugal
• Chair of Ferroelectrics UK, 2013
• Programme Chair International Symposium on Applied Ferroelectrics, 2010
• International Advisory board, International Conference on Ceramics 3, 2010
• Principal Editor, Journal of Materials Research
• Editorial Board of International Materials Review
• Winner of 'best Knowledge Transfer Partnership based on EPSRC funded research’, 2008.
• Winner of the Edward C. Henry award for best paper in the J. American Ceramics Society
(Electronic Division) 2001.
• EPSRC Mid-Range Facilities Committee, 2011
10 Most Cited Career Papers
1) Dielectric and Structural Characteristics of Ba-Based and Sr-Based Complex Perovskites as
Aa Function of Tolerance Factor, Reaney IM; Colla EL; Setter N, J. J. Appl, Phys., 33(7A) ,
3984-3990 (1994). (~400 citations, defines the fundamental crystal chemistry underpinning how the
temperature coefficient can be manipulated through the perovskite tolerance factor in complex
perovskites)
2) Microwave dielectric ceramics for resonators and filters in mobile phone networks, Reaney IM;
Iddles D, J. Am. Ceram. Soc, 89(7), 2063-2072 (2006). (~400 citations, defines how the quality
factor and temperature coefficient can be manipulated in a wide range of MW materials)
3) Effect of Structural-Changes in Complex Perovskites on the Temperature-Coefficient OF the
Relative Permittivity, Colla EL; Reaney IM; Setter N, J. Appl. Phys., 74( 5) , 3414-3425 (1993).
(~380 citations, 1st critical investigation of MW properties to recognize the role of octahedral
tilting in controlling properties)
4) Orientation of Rapid ThermallyAnnealed Lead-Zirconate-Titanate Thin Films on (111) Pt
Substrates, Brooks KG; Reaney IM; Klissurska R; et al., J . Mater. Res. , 9 (10 ), 2540-2553 (1994)
(~300 citations, established control of orientation for ferroelectric thin films for memory, sensor
and microactuator applications)
5) Spontaneous (Zero-Field) Relaxor-To-Ferroelectric-Phase Transition in Disordered,
Pb(Sc1/2Nb1/2)O3, Chu F; Reaney IM; Setter N, J. Appl. Phys.Volume: 77(4) , 1671-1676 (1995).
(~200 citations, redefined the nature of relaxor/ferroelectric transitions and illustrated the role of
local polar and chemical order)
6) Investigation of Pt/Ti Bi-Layer Metallization on Silicon for Ferroelectric Thin-Film
Integration, Sreenivas K; Reaney I; Maeder T; et al., J. Appl. Phys, 75(1) , 232-239 (1994). (~250
citations, established stable conditions by which Pt could be used as a substarte for ferroelectric
thin film deposition)
7) Fabrication and characterization of nanoscale, Er3+-doped, ultratransparent oxy-fluoride glass
ceramics, Tikhomirov VK; Furniss D; Seddon AB; et al., Appl. Phys. Lett., 81(11) , 1937 (2002).
(~200 citations, established the role of nanoscale precipitates in the optical properties of novel
functional glasses)
8) Use of Transmission Electron-Microscopy for the Characterization of Rapid Thermally
Annealed, Solution-Gel, Lead-Zirconate-Titanate Films, Reaney IM; Brooks K; Klissurska R; et
al., J. Am. Ceram. Soc . 77 (5), 1209-1216, (1994). (~180 citations, established the role of excess
PbO in controlling the properties of ferroelectric thin films for memory, sensor and microactuator
applications)
9) Microwave dielectric solid-solution phase in system BaO-Ln2O3-TiO2 (Ln = lanthanide cation),
Ubic R; Reaney IM; Lee WE, Int. Mater. Rev., 43(5), 205-219 (1998). (~130 citations, review of an
important MW dielectric system which resolved critical aspects of its crystal chemistry and
structure-property relations)
10) Crystal and domain structure of the BiFeO3-PbTiO3 solid solution, Woodward DI; Reaney IM;
Eitel RE; et al., J. Appl. Phys., 94(5) , 3313-3318 (2003). (~130 citations, established a detailed
understanding of a complex solid solution which is now the basis of high temperature
piezoelectrics)