Measuring Ferroelectrics on I16

Ferroelectric materials are key in modern technology, with applications ranging from sonar transducers and gyroscopes to ultrasound devices, optical switching, non-volatile memory, solar cells, and flexible electronics. In addition to their presence in our daily life, they are also rich in terms of the physics governing their behaviour. 

In this vein, I16 offers a wide range of experimental techniques for studying ferroelectric materials at different length scales. For example, resonant scattering has been used to determine the absolute crystallographic structure in a multi-domain polar material, KTiOPO₄ by measuring a single Bragg reflection across an absorption edge to obtain a polar domain contrast mechanism [1]. Thin films of SrTiO₃ have been studied using XRD, reciprocal space mapping and reflectivity measurements [2] and multiphasic complex solid solutions have be distinguished and tracked using diffuse multiple scattering [3]. Bragg coherent diffraction imaging has been used to investigate nano-crystallites as demonstrated for SrTiO₃, where the three-dimensional lattice strain field was imaged [4].

Beyond ferroelectrics, the rare combination of the parity (P) symmetry breaking occurring in ferroelectric materials with time (T) breaking symmetry defines the multiferroics: another class of functional materials which combines reversible electrical polarisation with reversible magnetic ordering [5]. Simultaneous P–T symmetry breaking may arise either accidentally in improper multiferroics, where coupling between the order parameters is weak, or directly from magnetic ordering that breaks inversion symmetry, leading to stronger coupling albeit typically smaller polarisation. Measurements at I16 helped clarify the origin of giant polarisation tunability driven by symmetric exchange interactions in systems such as GdMn₂O₅ [6]. Additionally, in BiFeO₃, the electric polarisation was shown to control magnetic domain structures through subtle relativistic effects [7]. This investigation progressed from bulk single crystals to thin films, where substrate-induced symmetry breaking modifies domain behaviour and reduces magnetic domain sizes from hundreds of micrometres to the sub-micrometre scale, requiring complementary length-scale sensitivity from I16 and I06 for full characterisation \cite{Price2016}.

In addition to their technological relevance, certain multiferroics can also provide model systems for exploring fundamental cosmological concepts. For example, studies of hexagonal manganite multiferroics at I16 have used multi-reflection BCDI to reveal one-dimensional topologically protected defects, which can be viewed as the crystallographic analogues of cosmic strings [9].

References

[1] Fabrizi, F., Thomas, P. A., Nisbet, G. & Collins, S. P. (2015). Acta Cryst. A71, 361-367.

[2] Leroy, L., Huang, S.-W., Chiu, C.-C., Ho, S.-Z., Dössegger, J., Piamonteze, C., Chen, Y.-C., Abreu, E., Bombardi, A., Yang, J.-C., & Staub, U. (2025). Nano Letters, 25(19), 7651–7657.

[3] Nisbet, A. G. A., Cain, M. G., Hase, T. & Finkel, P. (2023). J. Appl. Cryst. 56, 1046â1050.

[4] Yang, D., Suzana, A. F., Wu, L., Ha, S. S., Choi, S., Ngo, H. M., Nawaz, M. M., Kim, H., Liu, J., Treuherz, D., Zhang, N., An, Z., Nisbet, G., Porter, D. G., & Robinson, I. K. (2025). Physical Review B, 111(2), 24107.

[5] Spaldin, N.A., Ramesh, (2019) R. Nature Mater 18, 203–212.

[6] Lee, N., Vecchini, C., Choi, Y. J., Chapon, L. C., Bombardi, A., Radaelli, P. G., & Cheong, S.-W. (2013). Physical Review Letters, 110(13), 137203.

[7] Johnson, R. D., Barone, P., Bombardi, A., Bean, R. J., Picozzi, S., Radaelli, P. G., Oh, Y. S., Cheong, S.-W., & Chapon, L. C. (2013). Physical Review Letters, 110(21), 217206.

[8] Waterfield Price, N., Johnson, R. D., Saenrang, W., Maccherozzi, F., Dhesi, S. S., Bombardi, A., Chmiel, F. P., Eom, C.-B., & Radaelli, P. G. (2016). Physical Review Letters, 117(17), 177601.

[9] Najeeb, M. A., Serban, D., Porter, D. G., Lichtenberg, F., Collins, S. P., Bombardi, A., Spaldin, N. A., & Newton, M. C. (2025). Communications Materials, 6(1), 14.