Fig. 4: Magnetic properties of the deposited networks.

a Topographic micrograph of the network measured by AFM. b, The corresponding magnetic domain patterns of the network measured by MFM in the as-grown state. The green, yellow, orange, cyan, and magenta boxes are provided in comparison with other magnetic states. c, e Magnified views of the dotted square regions in (b). The macro-spin-like and vortex-like magnetic configurations obtained from micromagnetic simulation by relaxing magnetizations saturated magnetized in -y directions (d) and randomly distributed magnetizations (f). The size and geometry of the simulated network are set according to the AFM measurement. g–j The illustration of the configurations of the external magnetic field applied to the network. The three magnetic field profiles are applied to magnetize or demagnetize the network. k The magnetic domain pattern at remanence after exposure to a 0.02 T magnetic field, as indicated by the magnetic field profile above. The colored boxes are provided for comparison with those shown in (b) as a visual guide. l The magnetic domain at remanence after exposure to a 0.05 T magnetic field. m The magnetic domain pattern after ac demagnetization with a maximum magnetic field of 0.1 T, as shown in (j) above. The dotted circles in (l, m) illustrate that vortex-like magnetic patterns reappear after AC demagnetization. While the dotted boxes in (l,m) show that the macro-spin-like configurations have been switched by the external magnetic field. The MFM images in (c, e, k, l, m) share the same color bar as that inserted in (b).