Magnetic switching of nanoscale antidot lattices

Abstract

SummaryWe investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py) as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices.

Nanopatterned hard/soft bilayer magnetic antidot arrays with long-range periodicity

“…between 0º and 90º for square arrays and between 0º and 60º for hexagonal ones. The results, summarized in figure 5, are in agreement with previous studies showing a monotonic dependence of coercivity on the DVD of the MAAs (17), whereas coercivity values of more than 700 Oe in Co MAAs having 0.58 DVD and more than 500 Oe in Py MAAs having 0.69 DVD, are reported in the literature (21). Furthermore, it is worth noting that the coercivity values obtained in this study are much higher than those obtained for MAAs fabricated under the same conditions (identical equipment and sputtering parameters) but onto porous anodic alumina, which were reported in our previous publication (13).…”

“…The advantage of the top-down approach is that long-range order may be obtained up to mm-wide areas, and the ordering parameters of the hole arrays, as well as the hole size and shape, may be tailored at will. This allows for studying magnetic nanostructures unobtainable using bottom-up approaches, which exhibit defect-free lattices within an area that ranges from a few m 2 to about 20 m 2 at best (21), in addition to the fact that only hexagonal symmetry may be obtained. Furthermore, top-down nanofabricated arrays may be laterally confined at will and complex combinations of different MAA symmetries and sizes may be patterned at the same device -each serving a unique purpose -allowing for the realization of magnonic circuits (22).…”

Enhancement the perpendicular magnetic anisotropy of nanopatterned hard/soft bilayer magnetic antidot arrays for spintronic application

“…The lowest value of the magnetic surface coverage ratio about 28.5-31.4 % has been obtained for Co, Py, and Co/Py bilayer antidot arrays samples with hole diameter 93 nm, 94 nm, and 95 nm, respectively, and interhole distance P =107 ± 3 nm, being lower than the ones reported in ref. [18][19][20]. The wide variation of hole diameter, W, and C has enabled us to study the full possible geometric parameters of Co, Py, and Co/Py bilayer antidot films deposited on nanoporous alumina membrane and their effect on the magnetic properties, especially the magnetic anisotropy.…”

Magnetic properties of Fe3O4 antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction

“…More studies would be needed to obtain the threshold value of the lattice parameter at which the tendency changes. It is important to point out that the coercivities obtained by the AFIR technique are almost twice as high as those obtained with other techniques, considering similar geometrical and magnetic parameters [ 39 ].…”