Magnetic properties of periodically organized cobalt frameworks

Abstract

Periodically organized magnetic cobalt frameworks have been fabricated by a combination of colloidal self-assembly and electrochemical deposition. The ordered cobalt frameworks have a closed-packed face-centered-cubic inverse opal structure and are fabricated as micrometer-thick films. The size and density of the cobalt crystallites that compose the cobalt frameworks can be modified by a thermal annealing step following the electrodeposition. Comparison of the magnetic properties (studied by magneto-optical Kerr effect (MOKE) spectroscopy) of as-deposited and annealed samples reveals strong impact of the annealing process. Fitting the obtained MOKE response to a modified Langevin model reveals optimum values of coercivity, pinning site density, and inter-domain coupling for samples that are thermally annealed at 440 °C.

An Experiment‐Based Numerical Treatment of Spin Wave Modes in Periodically Porous Materials

“…3D magnetic antisphere lattices based on nickel inverse opals were fabricated by a combination of colloidal sphere self‐assembly and electrochemical infiltration . By varying the diameters of the polystyrene templating spheres, FCC nickel inverse opals with different lattice constants a were obtained.…”

“…Diverse routes to prepare 3D‐structured magnonic crystals have been assessed . However, research on the directional properties of 3D magnonic structures has been limited mainly to theoretical studies .…”

Temperature behavior of the local magnetization vectors in ferromagnetic inverted opal-like structures

“…It is found in [14][15][16][17] that Н С exhibits an oscillatory dependence on the thickness of IOLS films. A qualitative explanation of these oscillations was suggested within the model of the pinning of thin domain walls in narrow sections of an inverted structure (between matrix spheres).…”

“…A qualitative explanation of these oscillations was suggested within the model of the pinning of thin domain walls in narrow sections of an inverted structure (between matrix spheres). In other words, the authors [14][15][16][17] did not consider the spatial anisotropy of IOLS films, but made a statement that the narrow areas of such structures play a decisive role in the behavior of the magnetization vector.…”

“…Samples of inverted opal like structures based on cobalt, iron, nickel, and Ni 50 Fe 50 alloy have been studied previously by the method of SQUID magne tometry [14][15][16][17][18]. The effect of two dimensional anisotropy of a film on the value of the coercive field Н С in twice inverted nickel based opal was studied [18].…”