PhD Studentship: Unravelling the Giant Piezoelectric Effect in ferroics under in situ external stimuli using Diffuse Multiple Scattering [STU0454]

Website DiamondLightSou Diamond Light Source

Supervisors: Dr Gareth Nisbet from Diamond Light Source Ltd and Prof Thomas Hase from University of Warwick

Project description:

The interplay between stress, strain and electric field in complex multiphase oxides provides the technological underpinning of a plethora of technological applications ranging from sonar and switches to new transistors. The challenge is to correlate macroscopic observables with the crystal structure itself. In these oxide systems, close to the morphotropic phase boundary, small changes provided by external stimuli cause the system to undergo phase transitions with crystal domains evolving. It is the exact pathway over which this occurs that underpins the giant piezoelectric effect (GPE), the origin of which remains controversial. The ambiguity surrounding GPE is because the evolution pathways of the small domains are complex and exhibit both spatial and temporal variations with current experimental probes unable to map them. This project exploits new X-ray metrologies to overcome this, taking advantage of “single-shot” measurements which allow the lattice of multiple domains to be determined simultaneously under a range of external stimuli. To do this we will use Diffuse Multiple Scattering (DMS), a new metrology developed at Diamond using beams as small as 1 µm and a new sample environment developed by Electrosciences Ltd. which will be integrated into the I16 beamline. The project exploits artificial intelligence and machine learning algorithms to realise fast and accurate analysis and will make DMS an accessible user option at I16.

The project will benchmark the new approach using crystals and thin films of PMN-PT and PIN-PMN-PT and extend studies to spatially resolved analysis as well as explore the dynamics of the system. X-ray data will be recorded simultaneously with any applied optical, stress/strain and electric fields applied to correlate the atomic and the macroscopic responses. The DMS work will be supported with conventional diffraction studies at other beamlines including XMaS with preliminary studies at the University of Warwick and offline using the new sample environment.

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