Ferroelectrics

Ferroelectrics play an essential role in many high-tech products such as capacitors in mobile phones. The need for smaller and more efficient devices requires that the materials be designed with tailored functionality. This is hampered by a complex and often devastating effect from material defects on many length scales. With X-ray microscopy, we can zoom in on these materials and see defects directly, cf. the figure. This opens the door to use defective configurations as a design element instead of being an obstacle. This theme is funded i.a. via an ERC Starting grant and a Villum Foundation grant.

On the image are shown cross-sectional dark-field X-ray maps from the article in Nature Long-range symmetry breaking in embedded ferroelectrics.by Simons, Hugh & Haugen, Astri & Jakobsen, Anders & Schmidt, Søren & Stöhr, Frederik & Majkut, Marta & Detlefs, Carsten & Daniels, John & Damjanovic, Dragan & Poulsen, Henning (2018).  Individual domains are visible in the integrated intensity image (a), while the reconstructed strain (b) and lattice orientation (c) maps reveal the structural relationship between domain clusters. d, Local orientation is read from the colour key, where the integrated diffraction intensity distribution is superimposed as a contour map. Boundaries (black lines) in a, b and c are defined by local orientation gradients exceeding 0.5° µm⁻¹.