Figure 3. Bloch-Néel transition revealed by DW resistance measurements.
(a) a Bloch wall yields only an intrinsic contribution RLZ to the DW resistance. (b) As ϕ approaches 0 (Néel wall), an additional contribution from the AMR effect arises. (c) (top) Depinning efficiency as a function of Hx and (bottom) Resistance change induced by 20 DWs of alternating polarity, as a function of Hx (open diamonds) and Hy (filled triangles), measured on the same Pt(4)/Co(0.5)/Pt(2) sample. The dashed orange and solid purple line are a fit including the two resistance contributions, in which HK and HD have been taken from the fit of the depinning data. The DW resistance peaks around Hx = 20 mT due to the transition from Bloch to Néel. A decreasing background signal is present in both the Hy and the Hx data due to canting of the magnetization in the irradiated domain (d), leading to a lower intrinsic contribution RLZ. (e) DW resistance in Pt/Co/AlOx does not show the Bloch-Néel transition since Néel walls are highly stable.