Crafting and real-space imaging of non-collinear spin textures in multiferroic BiFeO3
Bismuth ferrite (BiFeO 3 , BFO) is the most widely studied single phase multiferroic and one of the very few that is magnetic and ferroelectric at room temperature . In the bulk, BFO is antiferromagnetic with a long-period spin cycloid that can be controlled by electric fields . In this talk I will show how epitaxial strain can be used to tune the cycloid period, stabilize a new cycloid and transform it into a pseudo-collinear antiferromagnetic state [3,4]. I will first show data from macroscopic probes such as Mössbauer spectroscopy or Raman spectroscopy, and then explain how these spin orders can be imaged in real space using a new scanning probe technique called nitrogen-vacancy (NV) center microscopy . In particular, NV microscopy supported by resonant elastic X-ray scattering brings insight into the spin textures at domain walls, where chiral magnetic objects form . These results demonstrate how BFO can be used as a versatile platform for the design of reconfigurable nanoscale artificial spin textures.
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Host: Prof. Tae Won Noh