Regensburg 2016 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 8: Focus Session: Ferroic Domain Walls II

DF 8.1: Topical Talk

Dienstag, 8. März 2016, 14:00–14:30, H25

Microscopic order parameters coupling at domain walls and its effect on macroscopic properties — •Saeedeh Farokhipoor — Device Materials Group, University of Cambridge, Cambridge, UK

Domain and domain wall (DW) engineering provides an alternative model to tune the physical properties of materials, typically done via conventional materials chemistry. The interplay of coexisting non-ferroelectric structural order parameters, ferroelectric and magnetic order parameters at the DWs in hexagonal manganites provides a new pathway to determine macroscopic properties by tuning the DW characteristics [1]. Here, I report different types of domain structures and DW types associated with the crystal growth conditions in hexagonal manganites. I show that differences in the DW polar state manifest themselves as variations in the conductivity measured macroscopically. In addition, local piezo force microscopy and X-ray diffraction enable us to determine the plane of the DWs and hence, their strain state. The latter findings are in very good agreement with the topographical study. Finally, these results show that DWs under strain lower the critical field of the magnetic phase transition compared to samples with strain-free DWs. In conclusion, I show that among all the complexity in the behavior and response of nano-features, it is possible to tune macroscopic responses by understanding the local state properties, which can be adjusted as easily as by thermal annealing and/or by the crystal growth method. [1] S. Artyukhin et al., Nat. Mater. 13 (2014)