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academies
November 22-23, 2018 | Paris, France
Journal of Materials Science and Nanotechnology | Volume: 2
Materials Physics and Materials Science
International Conference on
Phase transitions in Bi
0.5
Na
0.5
TiO
3
based Ferroelectrics
Yan H
Queen Mary University of London, UK
L
ead-free 0.94(Bi
0.5
Na
0.5
TiO
3
)–0.06(BaTiO
3
) (BNTBT) is a
potential piezoelectric candidate to replace lead-based PZT
ceramics. The thermal depoling temperaturesets theupper limit
for the high temperature application of piezoelectric materials.
Recently, an interface model was proposed to explain the
good resistance to thermal depoling of BNTBT-ZnO composite.
However, we found that the presence of ZnOwas not limited to
the interface but contributed intrinsically to the BNTBT lattice.
This played a critical role in the structural changes of BNTBT,
confirmedbyaunitvolumechangesupportedbyXRD,whichwas
further proved by Raman, EDS, and dielectric characterization
at different temperatures. The previous interface model is not
correct because BNTBT shows thermally stable piezoelectric
properties, even though there is no interface between BNTBT
and ZnO. The thermal depoling behaviour of BNTBT-based
materials is directly related to the transition temperature from
the rhombohedral phase to the tetragonal phase in our phase
transition model, which is consistent with four current peaks
in their ferroelectric loops close to the depoling temperature.
Speaker Biography
Yan H is a senior lecturer in materials at the school of engineering and materials science
in Queen Mary, University of London. He received his PhD in materials science and
technology from Shanghai Institute of Ceramics in 2001. Since that, he joined QMUL as
an academic visitor and research assistant. At QMUL, he was appointed as an academic
Fellow in 2011 and senior lecturer in 2015. His research area includes: processing and
analysis of the microstructures and properties of advanced materials with textured,
nano and metastable structures, covering dielectrics, ferroelectrics, thermoelectrics
and ceramic-CNT composites. He has over 100 publications that have been cited over
3600 times, and his publication H-index is 35 and has been serving as an editorial board
member of Advance in Applied Ceramics and Materials Research Bulletin.
e:
h.x.yan@qmul.ac.uk