Development of a Scanning Thermal Microscopy method for high-resolution spatial mapping of the electrocaloric effect

Proof-of-concept measurements are presented for a barium titanate (BTO) multi-layer ceramic capacitor (MLCC) to show that the technique is capable of measuring the EC response with sub-micron spatial resolution, with the ultimate maximum resolution possible likely to be limited by the tip radius. Subsequent chapters focus on the implementation of this new electrocaloric mapping technique on Prototype lead scandium tantalate (PST) MLCCs possessing high electrocaloric performance.

Local electrocaloric measurements have been compared to existing indirect and direct measurements of the same samples from literature and were found to be in good agreement. Clear spatial variation in the ECE was observed in a polished cross section of the samples. High voltage Kelvin Probe Force Microscopy Measurements performed in tandem with EC measurements to elucidate how the surface potential and local electric field influenced the EC response.

Finally, the effect of naturally-occurring and artificially-induced microstructural features on the spatial homogeneity of the ECE are trialled and discussed. <br><br><i>Thesis is embargoed until 31 July 2030.</i><br>