Nanoscale investigation of coupling phenomena in bismuth ferrite under continuously varied mechanical stress

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Being one of the very few multiferroic single-phase compounds at room temperature, bismuth ferrite (BFO) is currently a highly topical field of solid-state research. Apart from its potential for lead-free piezoelectric, magnetoelectric, photovoltaic or multilevel memory applications, the fundamental understanding of the subtle response of the strongly coupled ferroic properties of BFO to external fields defines an important goal in the physics of multiferroics. The in-depth study of how the electronic, ferroelectric, and magnetic configuration of BFO can be tuned, especially in thin films, by inducing mechanical stress via continuously variable external uniaxial sample bending stands in the focus of the current project. During in-situ substrate bending, macroscopic key properties – such as electronic structure, conductivity, electric and magnetic polarization and their mutual coupling – as well as the corresponding nanoscopic fingerprints will be analyzed. One main issue is the investigation of the nanoscale stress-induced behavior of the different ferroic domain types and their boundaries by the simultaneous application of electrically and magnetically sensitive scanning probe methods. Moreover, the aim is to optimize the ferroic parameters via the tunable external stress systematically.