Fig. 3: Field-driven DW motion in a FM–SAF lateral junction.
a, Schematic illustration and magneto-optical Kerr images of field-driven DW motion within the FM region (top left) and SAF region (top right), and \(\tau _P^H\)-dependent \(H_{\mathrm{{th}}}^i(i = {{{\mathrm{FM}}\,{{{\mathrm{or}}}}\,SAF}})\) in the DW thermally activated regime (bottom panel). The DW configuration is set to ↑↓ and its position is denoted by white vertical lines. The direction of DW motion in response to the field is depicted by yellow arrows. \(H_{\mathrm{{th}}}^{\mathrm{{FM}}}\) (orange triangles) and \(H_{\mathrm{{th}}}^{\mathrm{{SAF}}}\) (blue triangles) correspond to \(P_{\mathrm{{inj}}}^i = 0.5\) at each \(\tau _P^H\) value. Solid curves correspond to fits to \(H_{\mathrm{{th}}} \propto 1 - (1/E_H){{{\mathrm{ln}}}}(\tau _P^H/\tau _0)\) to obtain \(E_H^i(i = {{{\mathrm{FM}}\,{{{\mathrm{or}}}}\,SAF}})\). The error bars represent 25/75% probabilities. Scale bars, 5 µm. b, Plot of \(E_H^i\) versus EJ in the thermally activated regime at T = 300 K. Green solid line corresponds to EJ = EH. The error bars represent the standard deviation. c, Schematic illustration of DW energy landscape versus DW position for various Hz values (Hz = 0, middle; Hz > 0, top; Hz < 0, bottom). The DW configuration is ↑↓. When Hz = 0, the DW stays in the FM region. The depinning energy barriers in the FM and SAF regions correspond to \(E_H^{\mathrm{{FM}}}\) and \(E_H^{\mathrm{{SAF}}}\), respectively. d, Plot of \(P_{\mathrm{{inj}}}^{{{{\mathrm{FM}} \to {\mathrm{SAF}}}}}\) versus \(\tau _H^J\) in the thermally activated regime. Inset: Kerr microscope images of DWs for 0° ≤ θJ ≤ 60° after the application of a field up to 3 kOe for 2 h. The fact that\(P_{\mathrm{{inj}}}^{{{{\mathrm{FM}} \to {\mathrm{SAF}}}}} = 0\) is shown for all θJ and Hz values such that the different symbols all overlap.
