Shape-induced anisotropy in antidot arrays from self-assembled templates

Fabrication and magnetic properties of patterned NiFeMo films electrodeposited in self-assembled nanosphere templates J. Appl. Phys. 109, 054313 (2011); 10.1063/1.3561362 Reduced saturation magnetization in cobalt antidot thin films prepared by polyethylene oxide-assisted selfassembly of polystyrene nanospheres Appl. Phys. Lett. 96, 122504 (2010); 10.1063/1.3371692Oscillatory thickness dependence of the coercive field in three-dimensional anti-dot arrays from self-assembly Using self assembly from lyotropic liquid crystalline phases and from colloidal suspensions of polystyrene spheres templates, we have prepared well-ordered, nanostructured magnetic materials. We present the results of electrochemical deposition of magnetic metals and alloys in the interstitial space between these templates. This technique has enabled us to create magnetic nanostructures with three-dimensional achitectures on length scales of 4 nm-1 m. We find changes in coercive field, by more than 1 order of magnitude, dominated by the effects of the nanoscale shapes. Varying the parameters in the preparation allows us to produce materials with predetermined magnetic parameters. The templated electrodeposition technique offers the potential of a low-cost preparation method for submicron patterned magnetic media.

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“…3͒. Our results for different magnetic materials 12 give further support to the importance of domain wall pinning.…”

Section: Resultssupporting

confidence: 76%

Magnetic antidot arrays from self-assembly template methods

Zhukov

Goncharov

Groot

et al. 2003

Journal of Applied Physics

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“…2a). Our results for different magnetic materials [11] further support the importance of domain wall pinning.…”

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confidence: 78%

Coercivity of 3D nanoscale magnetic arrays from self-assembly template methods

Zhukov

Ghanem

Goncharov

et al. 2004

Journal of Magnetism and Magnetic Materials

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We present results of electrochemical deposition of magnetic metals and alloys in the pores of templates prepared by self-assembly from colloidal suspensions of polystyrene latex spheres. This technique has enabled us to create highly ordered magnetic nano-structures with 3D architectures on length scales ranging from 50-1000 nm. Varying the parameters in the preparation (sphere diameter, film thickness and composition) allows us to produce materials with predetermined magnetic parameters. Keywords: Nanostructures; Self-assembly; Anti-dots; Coercive field Efficient methods to fabricate magnetic patterned structures are required for the development of magnetic media with high recording density. Combining thin film growth techniques with sub-micron lithography is a standard solution for this task. However, for lateral dimensions below 100-200 nm relatively cheap and fast optical lithography techniques become inapplicable. The cost of ion or electron lithography is uneconomically high for industrial applications. Alternative routes are needed for creating highly ordered magnetic structures on length scales down to a few nanometers. In this paper we present results for magnetic nanostructured samples prepared by electrochemical deposition through different templates produced by self-assembly of polystyrene spheres.Well-ordered templates have been prepared using a very slow (3-5days) evaporation of a colloidal water suspension containing 0.5 wt% of polystyrene spheres. The details of the preparation method are described in Refs. [1][2][3]. Magnetic films with pore size 50-1000 nm have been prepared. Fig. 1 presents a scanning electron microscope (SEM) image of a Fe 0.5 Ni 0.5 film deposited trough a template of spheres with a diameter of 0.5 mm. The crystal structure, composition and morphology of the films were characterised using SEM, energy dispersive X-ray spectroscopy and X-ray diffraction.Magnetic measurements have been performed using several techniques: vibrating sample, SQUID, Hall probe (sensitive area 50 mm Â 50 mm) [4] magnetometers and magneto-optical Kerr effect rig. Most measurements have been done at room temperature with the magnetic field applied parallel to the film plane.We have studied the impact of nanostructuring on the magnetic properties of different magnetic films of cobalt, iron, nickel and soft magnetic alloy Fe 0.5 Ni 0.5 (both plain and patterned films had polycrystalline structure without texture). The magnetization loops revealed significant changes resulting from the nanoporous ARTICLE IN PRESS

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“…This creates socalled antidote or inverse sphere arrays of Ni. In a previous paper, we have shown the hexagonal symmetry of the coercivity in these structures [14]. Here we will show that the observed symmetry can be explained qualitatively by the micromagnetic simulation of only one small section of the patterned film.…”

Section: Introductionsupporting

confidence: 62%

Long range ordering in self-assembled Ni arrays on patterned Si

Gonzalez

Kiziroglou

et al. 2007

Journal of Magnetism and Magnetic Materials

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We have succeeded in aligning self-assembled structures by using a lithographically defined stripe. The 140 nm wide by 100 nm high SiO 2 strip is shown to guide the assembly of 500 nm latex spheres so that spheres are aligned along the strip and are in registration on either side of the strip. This method can be used to increase long-range ordering in magnetic storage systems without compromising the density. Inverse sphere Ni arrays were made by electrodeposition through the latex template. We also show that the hexagonal symmetry of the resulting inverse sphere Ni arrays can be simulated using the approach presented below. r

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Shape-induced anisotropy in antidot arrays from self-assembled templates

Cited by 6 publications

References 7 publications

Magnetic antidot arrays from self-assembly template methods

Magnetic antidot arrays from self-assembly template methods

Coercivity of 3D nanoscale magnetic arrays from self-assembly template methods

Long range ordering in self-assembled Ni arrays on patterned Si

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