Magnetization Reversal Process in 3D Permalloy Nanomatrix

Abstract

A 3D matrix created by self-alignment of nanowires and 2D antidots is reported. Interactions between nanowires and antidots leading to non-conventional magnetic properties in the 3D matrix are reported. While the easy-axis magnetization of the 3D matrix is dominated by shape anisotropy of the nanowires, the hard-axis magnetization reversal behavior is driven by the bottom 2D antidots. Detailed analysis reveals a defect-induced domain wall propagation process for the easy-axis-reversal process. Micromagnetic simulations show good agreement with experimental results.

Modified Spin Textures in a 3D Magnetic Lattice

“…The procedure for the magnetization reversal study is reported in detail in our previous literature. [ 26 ] The black arrows indicate the direction of the applied field. The white dotted rectangles show the location of the HGS.…”

“…These observed magnetic domain states for the easy‐axis reversal are similar to previously reported magnetic domain states of conventional 2D antidot matrix. [ 26,27 ]…”

“…More details on the angles were reported in the previous study. [ 26 ] The two fabrication parameters of the self‐aligned nanofabrication technique are 1) the angle between the incoming deposition beam and the sample, θ , and 2) the nanosphere mask orientation, Φ . The 3D magnetic lattice was fabricated using two subsequent deposition steps: the first step created antidot matrix with head‐on permalloy deposition at θ = 0° and Φ = 0°; the second step created a HGS array over the antidot matrix with permalloy deposition θ = 50° and Φ = 0°.…”

“…These observed magnetic domain states for the easy-axis reversal are similar to previously reported magnetic domain states of conventional 2D antidot matrix. [26,27] When the saturation field 3000 Oe is applied along the hard axis (Figure 2e), the antidot region shows the remnant singledomain state with the white arrow pointing toward the field direction. In contrast, the HGS layer shows a vortex which occupies the top portion of the HGS (indicated by a curved arrow) and a single-domain state in the remaining bottom portion (indicated by a straight arrow).…”

“…In a conventional 2D antidot matrix, the reversal process is only induced by the coherent rotation of its magnetic moments where its magnetic domain aligns along the field direction. [26,28] The difference in behavior is attributed to the extra HGS layer over the conventional antidot matrix, which forms a 3D magnetic lattice in the same material, demonstrating how one can design 3D structures to tailor properties of magnetic nanostructures.…”