This package will use a combination of X-ray diffraction and interferometry to measure displacement (or strain) in very small-scale piezoelectric materials. Both of these are non-contact techniques, ensuring that the measurement process has minimal impact on the results.
X-ray diffraction is a well know technique used for determining the structure of piezoelectric materials on the atomic scale, and interferometry is often used to measure micro and nanoscale displacements. However, combining them in a simultaneous measurement is quite a feat and has not previously been attempted. Using these techniques together will allow us to establish a direct link between global and atomic strain, effectively linking the measurement of strain between up to eight decades in length scales.  In addition, we will investigate how strain changes in these materials as you scale the sample size down,.  Being able to measure how the properties of materials change with size will be invaluable to help engineer new materials and devices, and miniaturise existing ones.

One challenge facing this package is that Interferometry is very sensitive to vibration and other environmental factors. X-ray measurements are typically performed in a very noisy environment (with vacuum pumps, moving parts with motors…) with a lot of resulting vibrations which could strongly affect the interferometry results.  In order to use these techniques effectively together, vibrations must be reduced or corrected for. Building a rigid sample-reference surface-interferometer system is the first step to reduce the vibrations. In addition, since not everything can be taken into account with this method, measuring the laboratory vibration modes very accurately, should allow the team to correct for them, or reduce them by identifying where they are coming from.

It is hoped that this package, by establishing how properties change with scale in piezoelectric materials, will help industry to develop new types of microelectronic devices. There is an increasing need for miniaturisation in all aspects, and particularly in electronics and computing. Piezoelectric materials could also provide a solution to the stagnating speed of modern computer processors. These materials create electric charges under stress or pressure, and therefore their electro-mechanical coupling could be exploited in computer technology, but the strain, and therefore the output, depends on several factors acting at different lengths scales, also changing with the scale of the material sample. In order to understand this process and utilise it, we first need to accurately characterise it.

Not only will this research help us understand the effect of electrically induced strain on these materials, it will also look at the effect of other forces such as temperature (useful as computer chips are now working at much higher temperatures of up to 100 degrees), magnetic field and frequency. It will also enable a lot of further research into other nanoscale materials.
The National Physical Laboratory is the lead on this work package, with collaborators from XMAS – the UK material science beamline managed by Universities of Liverpool and Warwick and located at European Synchrotron Radiation Facility (ESRF), France.

For more information on Work Package 1, please contact Carlo Vecchini at: