Nanostructure in Functional Ceramics
Lead Research Organisation:
University of Sheffield
Department Name: Materials Science and Engineering
Abstract
The functional properties of many ceramics are controlled principally by displacements of ions which create small electric dipoles across the unit cells of certain types of oxides. However, in order for these electric dipoles to affect the bulk properties, they must be cooperative, i.e. the displacemetns must occur in the same direction for at least several tens of unit cells. Functional properties are tailored for a specific application by modifying the direction and length over which the dipoles are cooperative as well as the temperature at which they occur (Tc). In ceramic capacitors which act as rf filters, a mesoscale heterogeneous distribution of dopants modifies the magnitude, direction and onset temperature of the dipoles, preventing the filter frequency from changing significantly with temperature. In piezoelectric ceramics, a nanoscale mixture of monoclinic, tetragonal and rhombohedral phases in which the direction/magnitude of the dipoles differs in each structure, optimises the charge/displacement produced. This programme aims to investigate the local nanostructure of ceramics using advanced analystical instrumentation and determine its relation to bulk properties (permittivity, dielectric loss, piezoelectricity). This understanding will be used to improve performance and develop new functional ceramics.
Organisations
Publications
Wu A
(2008)
Microstructural Characterization of Thick PZT films on Cu Foils Deposited by Electrophoresis
in Microscopy and Microanalysis
Wang S
(2010)
Leakage behavior and conduction mechanisms of Ba(Ti0.85Sn0.15)O3/Bi1.5Zn1.0Nb1.5O7 heterostructures
in Journal of Applied Physics
Wang S
(2010)
Enhanced tunable and pyroelectric properties of Ba(Ti0.85Sn0.15)O3 thin films with Bi1.5Zn1.0Nb1.5O7 buffer layers
in Applied Physics Letters
Pokorný J
(2011)
Use of Raman spectroscopy to determine the site occupancy of dopants in BaTiO3
in Journal of Applied Physics
Miao S
(2009)
Polar order and diffuse scatter in Ba(Ti1-xZrx)O3 ceramics
in Journal of Applied Physics
Maxim F
(2008)
Hydrothermal Synthesis and Crystal Growth Studies of BaTiO 3 Using Ti Nanotube Precursors
in Crystal Growth & Design
Levin I
(2010)
Reorientation of magnetic dipoles at the antiferroelectric-paraelectric phase transition of Bi 1 - x Nd x FeO 3 ( 0.15 = x = 0.25 )
in Physical Review B
Karimi S
(2009)
Crystal chemistry and domain structure of rare-earth doped BiFeO3 ceramics
in Journal of Materials Science
Karimi S
(2009)
Nd-doped BiFeO3 ceramics with antipolar order
in Applied Physics Letters
Hlinka J
(2011)
Angular dispersion of oblique phonon modes in BiFeO 3 from micro-Raman scattering
in Physical Review B
Description | The grant was designed to establish a combined experimental initiative in which Raman spectroscopy was used in tandem with advanced electron microscopy on a routine basis. The key findings were: 1) A new PbZrO3 structured AFE ceramic based on Nd doped BiFeO3. This is the first AFE/AFM structured ceramic and publication of the data has resulted in many research groups pursuing studies on this topic. 2) A new methodology of using Raman spectrosocpy to help determine site occupancy in perovskite structured ceramics. In the development of functional ceramics, it essential to know where dopant ions reside in the structure. This technique adds a new dimension to dopant studies and understanding defect structure/property relations in perovskites. 3) Sheffield is now able to act as a informal centre for Raman spectroscopy studies in the UK. The Raman microscope has been improved and a 3rd laser added. In situ, He and LN2 stages have been purchased along with a Diamond anvil pressure stage and an in house constructed poling stage. The Sheffield facility is now the leading Raman facility in the UK for the study of inorganic compounds. |
Exploitation Route | We are currently investigating Nd doped BiFeO3 for potential piezoelectric applications but to date there have no major breakthroughs. |
Sectors | Aerospace Defence and Marine Electronics |
Description | The grant has facilitated the development of the leading Raman spectroscopy facility in the UK for the study of inorganic compounds. The Raman has 3 lasers, in situ strain and poling stages and a LHe and LN2 cooling/heating stages. The discovery of a non PbO based AFE ceramic with the PbZrO3 strcutured has driven great interest in oxide research groups. Papers published during and subsequent to the grant are highly cited. The grant has allowed MSE at Sheffield to establish the leading UK inorganic Raman facility which has been utilised by a number of external groups, e.g. Leeds (A.J. Bell and Manchester (D. Hall). New techniques have been developed on this and related grants to study perovskites using Raman spectroscopy. The use of electron diffraction in combination with Raman has facilitated a deeper understanding of the crystal structure of perovskites. Some PbO based compounds such as PbZrO3 and PbHfO3 are know to have AFE structures. The discovery of a non PbO version based on Nd doped BiFeO3 is a significant data point in terms of the crystal chemistry of perovskites and it is hoped that this will act as a base for the development of new materials. Beneficiaries: Multiferroics community and UK perovskite community (Raman facility) Contribution Method: The grant facilitated the development of the Raman facility at Sheffield which has resulted in further funding and increased quality of research output |
First Year Of Impact | 2011 |
Sector | Aerospace, Defence and Marine,Electronics |
Impact Types | Societal |
Description | EPSRC |
Amount | £280,149 (GBP) |
Funding ID | EP/G069069/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 09/2009 |
End | 09/2012 |
Description | EPSRC |
Amount | £392,058 (GBP) |
Funding ID | EP/I038934/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 01/2011 |
End | 12/2014 |
Description | EPSRC |
Amount | £20,964 (GBP) |
Funding ID | EP/J009679/1 + EP/I038934/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 05/2012 |
End | 12/2012 |
Description | EPSRC |
Amount | £23,635 (GBP) |
Funding ID | EP/H048049/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 03/2010 |
End | 07/2010 |
Description | EPSRC |
Amount | £30,250 (GBP) |
Funding ID | EP/I033319/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 03/2010 |
End | 07/2010 |
Description | EPSRC |
Amount | £23,635 (GBP) |
Funding ID | EP/H048049/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 03/2010 |
End | 07/2010 |
Description | EPSRC |
Amount | £280,149 (GBP) |
Funding ID | EP/H048049/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 09/2009 |
End | 09/2012 |
Description | Conference Invited talks (international) Invited Seminars (National) |
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 multiple invited presentations at international conferences, e.g. Electronic Materials and their Applications, Electroceramics, International Symposium on Applied Ferroelectrics. The audience members varied from post graduate researchers to faculty in other universities (professional practioners). The research was also presented at Glasgow University and Liverpool University in their seminar series. |
Year(s) Of Engagement Activity | 2009,2011,2012,2013,2014 |