Figure 4
Magnetic potential energy of half-disk patterns in the magnetic spider web. (a) The minimum potential energy is plotted for a clockwise rotating field along patterns 1 and 2 in T-junction. The energy minima allow the particle to cross the T-junction and move toward the linear forward direction instead of going to flat edge. The pattern 1 (red line) has the minimum energy than the pattern 2 (black dotted line). The inset shows the schema of the particle trajectory along patterns 1 and 2. (b) The minimum potential energy is plotted for a counterclockwise rotating field along the patterns (1) and (2). The minimum potential energy is lowered when the particle moves along pattern 2 instead of pattern 1 which preventing the crossing over a linear segment because of the presence of energy barrier at the junction point make obstacle for the particle movement (the inset shows the schematic of the particle trajectory along each path). (c) The minimum potential energy is plotted for a counterclockwise rotating field along the edge pattern of spiral. Inset shows the schematic of the edge of the spiral pattern (pattern 3). The lower energy minima of linear curve of pattern 3 than that of flat surface indicates that the particles cannot move on the flat surface toward the flat edge of pattern 2 and revolve around edge of the pattern 3 by applying counterclockwise rotating field. (d) The potential energy landscape of particles indicates the local energy minimums from θ=−60° to −50° are revealed to across the narrow connection between patterns 2 and 3 (blue and red colors designate the energy minima and maxima, respectively).
