Plenary Session 4 (8:30 ~ 9:50, Nov. 15, 2023)

Chair: Professor Yoshihiro Kuroiwa (Hiroshima University, Japan)

Plenary Talk - 7

 Take it to the Limit: A story of piezoelectric materials and devices for extreme conditions

Andrew J Bell

The University of Leeds and Ionix Advanced Technologies Ltd, UK

 

This presentation will tell the story of how a curiosity-driven, ferroelectric materials research topic developed into a $2 million p.a. business, manufacturing industrial ultrasound transducers for use under extreme conditions. On that journey we discovered some interesting materials science, we learnt how to process materials on the edge of instability, we overcame our academic sensitivities in order to finance a spin-out company and followed some unexpected paths to gain moderate commercial success. The talk aims to provide a contemporary and perhaps idiosyncratic view of both the science and business of piezoelectric materials.

 

BiFeO3-PbTiO3 is a ferroelectric solid solution with a morphotropic phase boundary (MPB) between the perovskite rhombohedral and tetragonal phases. It has a number of interesting features including the high Curie temperature (635°C at the MPB), an unprecedented spontaneous strain (≈20%) on the tetragonal side of the MPB and the >300 K discontinuity in the antiferromagnetic Néel temperature across the MPB. These features provide a number of exciting opportunities in terms of exploiting the high temperature piezoelectricity and coupling the antiferromagnetism to strain and electric field, whilst the extreme tetragonality provides challenges in materials fabrication. Whilst studying these features the Functional Ceramics Group at the University of Leeds discovered methods to overcome the technical barriers to exploiting the piezoelectric properties and to produce materials capable of “PZT-like” performance up to and beyond 500°C.

 

As most established piezoelectric materials producers felt that BiFeO3 might be a challenge too far, the University supported the founding of a company, funded by venture capital and private finance, to commercialise the new material. Although there was a market ready for devices spanning the materials’ temperature capability, no potential customers had the capability to build the material into high temperature transducers. Hence, what started as a materials company transformed into a device company, with products in the industrial ultrasound, automotive, aerospace and electronics sectors.

 

About the speaker

 

 

Professor Andrew Bell was educated at the University of Birmingham, UK (BSc Physics, 1978) and the University of Leeds (PhD Ceramic Science and Engineering, 1984). He has been Professor of Electronic Materials at the University of Leeds, School of Chemical and Process Engineering since 2000. He previously spent almost 15 years in industrial research posts and 4 years as a Senior Scientist in the Ceramics Laboratory at EPFL, Switzerland.

At the University of Leeds, he was Pro-Dean for Research in the Faculty of Engineering (2003-07) and Head of the School of Chemical & Process Engineering (2011-15). He teaches modules in Materials Science and Engineering at all levels from 1^st year undergraduate (Introduction to Materials Science) through to MSc (Materials for Electronic Applications). He is currently Director of the undergraduate degree programme in Materials Science and Engineering at the University of Leeds/Southwest Jiaotong University Joint School of Engineering in Chengdu.

He has undertaken research on a wide range of topics in ferroelectric and dielectric materials, encompassing basic science, materials processing, structural & electrical characterization and device physics, including pyroelectric materials and devices, microwave dielectrics and piezoelectrics. He has published over 200 papers with a total of more than 6000 citations.

From 2000 onwards, his research focussed almost exclusively on piezoelectric materials, particularly on those with capabilities beyond those of PZT. In 2011 he founded Ionix Advanced Technologies Ltd to exploit the new high temperature piezoelectric compounds emerging from his research group.

Prof. Bell was elected a Fellow of the Royal Academy of Engineering in 2016 and was elevated to Fellow of IEEE in 2019. He was awarded the Verulam Medal of the Institute of Materials in 2014. He has received the IEEE’s Ferroelectrics Recognition Award (2012) and Robert E Newnham Ferroelectrics Award (2022). He is currently the 2023 IEEE-UFFC Distinguished Lecturer in Ferroelectrics.