Fig. 2: Correlation of the magnetic cycloid.
From: Switching the spin cycloid in BiFeO3 with an electric field
a From PFM, BFO samples show stripe 71° ferroelectric domains along \([100]\) that are characteristic of the material. NV images taken at the same location show that \(B({{{{{\boldsymbol{r}}}}}})\) and \(P({{{{{\boldsymbol{r}}}}}})\) can be exactly mapped where \({{{{{\boldsymbol{k}}}}}}{{{{{\boldsymbol{\perp }}}}}}{{{{{\boldsymbol{P}}}}}}\). b Illustration showing the symmetry allowed directions of \({{{{{\boldsymbol{k}}}}}}\) and the change across the 71° ferroelectric domain wall. Because the in-plane variant of \({{{{{\boldsymbol{k}}}}}}\) (red) is favored and this is tied to the direction of \({{{{{\boldsymbol{P}}}}}}\), these domain walls in BFO give rise to a 90° rotation in \({{{{{\boldsymbol{k}}}}}}\). This is shown more closely in (c, d), where the local \({{{{{\boldsymbol{P}}}}}}\) can be mapped to \(B\left({{{{{\boldsymbol{r}}}}}}\right)\) with continuous reorientations occurring every ~200 nm at domain walls.
