Nanofabricated and self-assembled magnetic structures as data storage media

Terris, B. D.; Thomson, Thomas

doi:10.1088/0022-3727/38/12/r01

Cited by 792 publications

(541 citation statements)

References 214 publications

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“…The control of the magnetic properties of ferromagnetic thin films is an important topic for both the fundamental understanding of low-dimensional magnetism and a broad range of applications, such as magnetic recording media [1], sensors [2], and magnonic devices [3,4]. A strong dependence of the magnetization reversal mechanisms on the microstructure and the presence of defects makes magnetic properties hardly controllable.…”

Section: Introductionmentioning

confidence: 99%

Magnetic antidot to dot crossover in Co and Py nanopatterned thin films

et al. 2014

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The crossover from antidot to dot magnetic behavior on arrays patterned in a ferromagnetic thin film has been achieved by modifying only the geometry. A series of antidot arrays has been fabricated on cobalt with fixed diameter d and by reducing the period of the array p from p d to p < d. A dramatic change in the coercivity dependence with p, correlated with a significant modification in the magnetic domain structure observed by x-ray photoemission electron microscopy, evidences the crossover. An intermediate regime has been found between the superdomain structure present in antidot arrays and the array of astroid-state noncorrelated dots. The study has been reproduced for a different ferromagnetic material, permalloy, and supported by micromagnetic simulations.

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Section: Introductionmentioning

confidence: 99%

Magnetic antidot to dot crossover in Co and Py nanopatterned thin films

et al. 2014

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“…Although optical lithography has high throughput, the smallest size of features that can be produced is limited by the long optical wavelength. Among many nanofabrication methods, [10][11][12][13][14][15] a promising technique is based on masks with sub-100-nm self-assembled pores. Such masks, for example, can be fabricated by the anodization of aluminum under appropriate experimental conditions.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and structural characterization of highly ordered sub-100-nm planar magnetic nanodot arrays over 1cm2 coverage area

Roshchin

Batlle

et al. 2006

Journal of Applied Physics

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Porous alumina masks are fabricated by anodization of aluminum films grown on both semiconducting and insulating substrates. For these self-assembled alumina masks, pore diameters and periodicities within the ranges of 10-130 and 20-200 nm, respectively, can be controlled by varying anodization conditions. 20 nm periodicities correspond to pore densities in excess of 10 12 per square inch, close to the holy grail of media with 1 Tbit/ in. 2 density. With these alumina masks, ordered sub-100-nm planar ferromagnetic nanodot arrays covering over 1 cm 2 were fabricated by electron beam evaporation and subsequent mask lift-off. Moreover, exchange-biased bilayer nanodots were fabricated using argon-ion milling. The average dot diameter and periodicity are tuned between 25 and 130 nm and between 45 and 200 nm, respectively. Quantitative analyses of scanning electron microscopy ͑SEM͒ images of pore and dot arrays show a high degree of hexagonal ordering and narrow size distributions. The dot periodicity obtained from grazing incidence small angle neutron scattering on nanodot arrays covering ϳ2.5 cm 2 is in good agreement with SEM image characterization. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2356606͔ INTRODUCTIONNanostructured magnets have attracted great attention recently due to their unique magnetic properties which are completely different from those of continuous films and bulk materials. [1][2][3][4] In addition, nanoscale studies may shed light on the heavily investigated mechanism of exchange bias 5-9 existing in ferromagnet ͑FM͒-antiferromagnet ͑AF͒ bilayers. Fabrication of sub-100-nm FM single layer and FM/AF bilayer nanostructures offers a great opportunity for research on fundamental magnetism at the nanoscale.A variety of methods are used for nanofabrication, including electron beam and optical lithography. The low throughput and high cost of electron beam lithography lead to limited applicability for the fabrication of nanopatterns with large coverage area. Although optical lithography has high throughput, the smallest size of features that can be produced is limited by the long optical wavelength. Among many nanofabrication methods, 10-15 a promising technique is based on masks with sub-100-nm self-assembled pores. Such masks, for example, can be fabricated by the anodization of aluminum under appropriate experimental conditions. [16][17][18][19][20][21][22] Arrays of nanopores with tunable pore diameter covering more than 1 cm 2 demonstrate the potential application of porous alumina ͑AlO x ͒ masks for nanostructure fabrication. Previously, alumina membranes obtained from the anodization of thick ͑Ͼ100 m͒ aluminum foils were mostly used for the fabrication of nanowires. [23][24][25][26][27][28][29][30] These nanowires were grown by electrodeposition, which cannot be easily adapted for the fabrication of nanodots with controlled and uniform thickness. Moreover, this method requires transfer of the alumina membranes onto a substrate. Insufficient adhesion between the membrane and substrate,...

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“…3,4 The physical properties of these nanostructures are strongly affected by the enhanced role of surfaces, symmetry breaking and finite size, etc. In addition to experimental approach, numerical methods become an alternative route to study and to understand the influence of different parameters on the structural and magnetic properties of the nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Modeling of hysteresis loops by Monte Carlo simulation

et al. 2015

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Recent advances in MC simulations of magnetic properties are rather devoted to non-interacting systems or ultrafast phenomena, while the modeling of quasi-static hysteresis loops of an assembly of spins with strong internal exchange interactions remains limited to specific cases. In the case of any assembly of magnetic moments, we propose MC simulations on the basis of a three dimensional classical Heisenberg model applied to an isolated magnetic slab involving first nearest neighbors exchange interactions and uniaxial anisotropy. Three different algorithms were successively implemented in order to simulate hysteresis loops: the classical free algorithm, the cone algorithm and a mixed one consisting of adding some global rotations. We focus particularly our study on the impact of varying the anisotropic constant parameter on the coercive field for different temperatures and algorithms. A study of the angular acceptation move distribution allows the dynamics of our simulations to be characterized. The results reveal that the coercive field is linearly related to the anisotropy providing that the algorithm and the numeric conditions are carefully chosen. In a general tendency, it is found that the efficiency of the simulation can be greatly enhanced by using the mixed algorithm that mimic the physics of collective behavior. Consequently, this study lead as to better quantified coercive fields measurements resulting from physical phenomena of complex magnetic (nano)architectures with different anisotropy contributions.

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Nanofabricated and self-assembled magnetic structures as data storage media

Cited by 792 publications

References 214 publications

Magnetic antidot to dot crossover in Co and Py nanopatterned thin films

Magnetic antidot to dot crossover in Co and Py nanopatterned thin films

Fabrication and structural characterization of highly ordered sub-100-nm planar magnetic nanodot arrays over 1cm2 coverage area

Modeling of hysteresis loops by Monte Carlo simulation

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