Ni-Co Alloy and Multisegmented Ni/Co Nanowire Arrays Modulated in Composition: Structural Characterization and Magnetic Properties

Méndez, Miguel; González, Silvia; Vega, V.; Teixeira, Jose M.; Hernando, B.; Luna, Carlos; Prida, V.M.

doi:10.3390/cryst7030066

Cited by 42 publications

(30 citation statements)

References 52 publications

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“…The ranges of radius and interwall distances of the simulated nanowire arrays are inside the ranges of the synthesized nanowire arrays: experimentally synthesized ferromagnetic nanowire arrays with diameter in the range 100-2000 Å, interwall distance in the range between 300 and 10 000 Å, together with one micrometer long are typical and suitable for basic science research and technological applications [51,52,[54][55][56][57][58]. Nanowire arrays with narrow internanowire distances are useful for magnetic recording media.…”

Section: Description Of the Ni And Co Periodic Nanowire Arraysmentioning

confidence: 93%

“…D s hcp-Co [41] 2000 4800 hcp-Co [41] 4000 8300 fcc-Co and hcp-Co [51] 150 1000 fcc-Co and hcp-Co [51] 700 1000 fcc-Ni [38] 300 1050 fcc-Ni [14,58] 180-330 650 fcc-Ni [14,58] 350-830 1050 fcc-Ni and hcp-Co [52] 350-5000 ?10000 fcc-Ni and Co [56] 500 1000 fcc-Ni [57] 500 1000 fcc-Ni, hcp-Co and Ni/Co [54] 450 1050 hcp-Co and CoNi [55] 350 1050 type of array (square or hexagonal) and the interwall distance are plotted in figures 2 and 3, for a fixed value of the nanowire radius. The fixed values of the radii match the experimental values of the radii of fcc-Ni, fcc-Co and hcp-Co nanowires found in the scientific literature: 175 Å for fcc-Ni [14,55] and 75 Å for fcc-Co and hcp-Co [51].…”

Section: Nanowirementioning

confidence: 99%

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Magnetostatic dipolar anisotropy energy and anisotropy constants in arrays of ferromagnetic nanowires as a function of their radius and interwall distance

Cabria

Prida

2020

J. Phys. Commun.

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Magnetostatic dipolar anisotropy energy and the total dipolar anisotropy constant, K total , in periodic arrays of ferromagnetic nanowires have been calculated as a function of the nanowire radius, the interwall distance of the nanowires in the arrays and the geometry of the array (square or hexagonal), by using a realistic atomistic model and the Ewald method. The simulated nanowires have a radius size up to 175 Å that corresponds to 31 500 atoms, and the simulated nanowire arrays have interwall distances between 35 and 3000 Å. The dependence of total magnetostatic dipolar anisotropy constant on the nanowire radius, their interwall distance and the type of array symmetry has been analyzed. The total dipolar anisotropy constant, which is the sum of the intrananowire dipolar anisotropy constant, K intra , due to the dipolar interactions inside an isolated nanowire and the main responsible of the shape anisotropy, and of the internanowire dipolar anisotropy constant, K inter , due to the magnetostatic dipolar interactions among nanowires in the array, have been calculated and compared with the magnetocrystalline anisotropy constant for three nanowire compositions and their crystalline structures. The simulations of the nanowire arrays with large interwall distances have been used to calculate the intrananowire anisotropy constant, K intra , and to analyze the competition between the intrananowire, internanowire and magnetocrystalline anisotropies. According to some magnetic theories, the ratio | | K K inter intra equals to the areal filling fraction of a nanowire array. Present calculations indicate that the equation for the areal filling fraction matches perfectly for any interwall distance and radius of Ni and Co nanowire arrays. This first equation is used to write a general equation that relates the radius and interwall distance of nanowire arrays with the intrananowire, internanowire and magnetocrystalline anisotropies. This general equation allows to design the geometry of nanowire arrays with the desired orientation of the easy magnetization axis.

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Section: Description Of the Ni And Co Periodic Nanowire Arraysmentioning

confidence: 93%

Section: Nanowirementioning

confidence: 99%

Magnetostatic dipolar anisotropy energy and anisotropy constants in arrays of ferromagnetic nanowires as a function of their radius and interwall distance

Cabria

Prida

2020

J. Phys. Commun.

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“…The most frequently studied anodic oxides are hexagonally arranged anodic aluminum oxide (AAO) [ 1 ] and nanoporous or nanotubular anodic titanium oxide (ATO) [ 2 ]. Intensive research on those two nanostructured materials has incited significant progress in: electrochemical and optical sensing [ 3 , 4 ], nanofabrication [ 5 ], photonic crystals [ 6 ], information optical coding [ 7 ], filtration and kidney dialysis [ 8 ], drug releasing platforms [ 9 ], biomaterials performance [ 10 ], renewable energy harvesting [ 11 , 12 ], the removal of greenhouse gases [ 13 ], magnetic materials [ 14 ], surface-enhanced Raman spectroscopy [ 15 ], plasmonic materials [ 16 ], structural color generation [ 17 ], tunable contact angle surfaces [ 18 , 19 ], and tunable band gap materials [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

Review of Fabrication Methods, Physical Properties, and Applications of Nanostructured Copper Oxides Formed via Electrochemical Oxidation

Stępniowski

Misiołek

2018

Nanomaterials

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Typically, anodic oxidation of metals results in the formation of hexagonally arranged nanoporous or nanotubular oxide, with a specific oxidation state of the transition metal. Recently, the majority of transition metals have been anodized; however, the formation of copper oxides by electrochemical oxidation is yet unexplored and offers numerous, unique properties and applications. Nanowires formed by copper electrochemical oxidation are crystalline and composed of cuprous (CuO) or cupric oxide (Cu2O), bringing varied physical and chemical properties to the nanostructured morphology and different band gaps: 1.44 and 2.22 eV, respectively. According to its Pourbaix (potential-pH) diagram, the passivity of copper occurs at ambient and alkaline pH. In order to grow oxide nanostructures on copper, alkaline electrolytes like NaOH and KOH are used. To date, no systemic study has yet been reported on the influence of the operating conditions, such as the type of electrolyte, its temperature, and applied potential, on the morphology of the grown nanostructures. However, the numerous reports gathered in this paper will provide a certain view on the matter. After passivation, the formed nanostructures can be also post-treated. Post-treatments employ calcinations or chemical reactions, including the chemical reduction of the grown oxides. Nanostructures made of CuO or Cu2O have a broad range of potential applications. On one hand, with the use of surface morphology, the wetting contact angle is tuned. On the other hand, the chemical composition (pure Cu2O) and high surface area make such materials attractive for renewable energy harvesting, including water splitting. While compared to other fabrication techniques, self-organized anodization is a facile, easy to scale-up, time-efficient approach, providing high-aspect ratio one-dimensional (1D) nanostructures. Despite these advantages, there are still numerous challenges that have to be faced, including the strict control of the chemical composition and morphology of the grown nanostructures, their uniformity, and understanding the mechanism of their growth.

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“…Furthermore, nanostructured materials based on irongroup alloys with diameters about, or smaller than 100 nm, can result in interesting properties. Thus, ferromagnetic (Fe, Co, Ni and related alloys) nanowires and nanotubes have gained attention recently due to the ability to tailor their magnetic properties [36][37][38][39][40], having potential applications in the fields of magneto-electronics [41], high sensitive giant magnetoresistance (GMR) sensors [42,43] or catalysis [44]. It has been found that coercivity, saturation magnetization, and remnant magnetization are strongly dependent on the size, morphology, crystalline structure and composition of nanowires [45,46].…”

Section: Introductionmentioning

confidence: 99%

Electrodeposition of Iron-Group Alloys into Nanostructured Oxide Membranes: Synthetic Challenges and Properties

Cesiulis

Tsytsaru

Podlaha

et al. 2018

CNANO

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Background: Quasi-one dimensional nanostructures: nanowires, nanotubes, nanorods, nanobelts/nanoribbons and complex "nanowire-nanoparticle" composites have been synthesized over the years. These nanostructures are particularly appealing due to their specific properties defined by their high aspect ratio: two dimensions are in the nanoscale range and one dimension is in the microscale. Methods:One of the well-designed approaches for the synthesis of such nanostructured materials is template-assisted fabrication combined with electrodeposition. The fabrication approaches for the growth of iron-group alloy nanostructures inside nanoporous oxide membranes by means of different electrodeposition techniques, and the resulting unique properties and potential applications of this type of materials are reviewed. Results:Arrays of nanostructures can be obtained by filling a porous oxide template that contains a large number of straight cylindrical, nano-sized diameter holes. Generalities of metals electrodeposition into nanoporous oxide membranes are discussed. Measures to minimize the nonuniformity of deposits inside pores need to be addressed to thin the barrier layer, to control hydrogen evolution and to improve mass transport inside the pores. Examples of binary and ternary iron group alloys grown inside nanoporous oxide templates are provided. Catalytic hydrogen evolution and methanol oxidation on the nanowires arrays are described. The "sample size effect" on the magnetic properties of materials and the electrodeposition of multilayered structures necessary for giant magnetoresistance (GMR) are discussed in details. Conclusion:Electrodeposition of binary and ternary iron-group alloys confirm that controlling alloy composition inside nanopores is still a challenge. composites [7] have been synthesized over the years. These nanostructures are particularly appealing due to their specific properties defined by their high aspect ratio: two dimensions are in the nanoscale range and one dimension is in the microscale. One of the well-designed approaches for the synthesis of such nanostructured materials is template-assisted fabrication combined with electrodeposition, first reported by Possin [8] in track etched mica films, and expanded upon by others with different materials and templates [2,[9][10][11][12][13][14]. However, the self-organized porous anodic aluminum oxide (AAO) membrane has become one of the most often used templates for tunable synthesis of different nanostructured materials [15,16].

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Ni-Co Alloy and Multisegmented Ni/Co Nanowire Arrays Modulated in Composition: Structural Characterization and Magnetic Properties

Cited by 42 publications

References 52 publications

Magnetostatic dipolar anisotropy energy and anisotropy constants in arrays of ferromagnetic nanowires as a function of their radius and interwall distance

Magnetostatic dipolar anisotropy energy and anisotropy constants in arrays of ferromagnetic nanowires as a function of their radius and interwall distance

Review of Fabrication Methods, Physical Properties, and Applications of Nanostructured Copper Oxides Formed via Electrochemical Oxidation

Electrodeposition of Iron-Group Alloys into Nanostructured Oxide Membranes: Synthetic Challenges and Properties

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