Magnetic behavior of electrodeposited cobalt nanowires using different electrolytic bath acidities

Caffarena, V.R.; Guimarães, A.P.; Folly, W.S.D.; Silva, E.M.; Capitaneo, Jefferson Leixas

doi:10.1016/j.matchemphys.2007.07.016

Cited by 22 publications

(8 citation statements)

References 11 publications

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“…As for the micrometric fibers, the ZFC curve (Figure ) rapidly increases with temperature below 6 K and linearly between 17 and 380 K, which can be attributed to different mechanisms of magnetic alignment. The well-pronounced peak around 6 K can be ascribed to some small Co particles with a volume distribution whose blocking temperatures are around 6 K. From this measured T B , it is possible to estimate the particles’ size using the relation K a V = 25 k B T B where K B is the boltzman constant, and K a V is the anisotropy energy barrier . Thus, the upper volume of these small particles can be estimated at 1.7 nm using an anisotropy constant of 4.1 × 10 5 J m −3 , calculated for Co nanotubes with R = 90 nm and H = 60 μm .…”

Section: Resultsmentioning

confidence: 99%

“…The well-pronounced peak around 6 K can be ascribed to some small Co particles with a volume distribution whose blocking temperatures are around 6 K. From this measured T B , it is possible to estimate the particles' size using the relation K a V ) 25k B T B where K B is the boltzman constant, and K a V is the anisotropy energy barrier. 29 Thus, the upper volume of these small particles can be estimated at 1.7 nm using an anisotropy constant of 4.1 × 10 5 J m -3 , calculated for Co nanotubes with R ) 90 nm and H ) 60 µm. 30 This result is consistent with the aggregation process proposed to explain the growth mechanism of these micrometric fibers.…”

Section: Magnetic Properties Of Cobalt Fibersmentioning

confidence: 99%

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Controlled Elaboration and Magnetic Properties of Submicrometric Cobalt Fibers

et al. 2008

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Hexagonal close-packed cobalt fibers with a narrow size distribution and a submicrometric diameter have been successfully synthesized using a modified polyol process in the presence of an applied magnetic field of 500 Oe. The X-ray diffraction (XRD) and the scanning electron microscopy characterization showed that the structure, size, morphology, and dispersion of the as-prepared fibers were widely influenced by the synthesis parameters (hydrolysis ratio, reactant concentration, reaction temperature, and time). The selected area electron diffraction pattern revealed that the as-prepared fibers are polycrystalline. Magnetic measurements on cobalt samples showed enhancement of their ferromagnetic properties, which may be attributed to their anisotropic shape. Irreversibility in the zero-field-cooling and field-cooling measurements was observed and could be interpreted in terms of the unblocking of magnetization of small-domain particles and domain wall depinning of larger multidomain particles.

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Section: Resultsmentioning

confidence: 99%

Section: Magnetic Properties Of Cobalt Fibersmentioning

confidence: 99%

Controlled Elaboration and Magnetic Properties of Submicrometric Cobalt Fibers

et al. 2008

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“…At room temperature, the magnetocrystalline anisotropy constant of bulk hcp cobalt was determined to be K 1 = 5.0 × 10 6 erg/cm 3 , while the shape anisotropy of magnetic nanowires was reported to be K s = π M 2 s = 6.10 6 erg/cm 3 [21]. From both the basic and applied research perspectives, a clear understanding of the effects of synthesis parameters (e.g., deposition current and time, pH solution) [22,23,24,25,26,27] and morphology (e.g., wire length and diameter) [6,9,28,29] on the magnetic properties of ordered nanowire arrays is essential. Despite some previous efforts [16,17], effects of the wire diameter on the magnetic properties of the ordered CoNiP nanowire arrays remained to be investigated.…”

Section: Introductionmentioning

confidence: 99%

Magnetization Reversal and Magnetic Anisotropy in Ordered CoNiP Nanowire Arrays: Effects of Wire Diameter

Thiem

Phan

2015

Sensors

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Ordered CoNiP nanowires with the same length of 4 µm and varying diameters (d = 100 nm–600 nm) were fabricated by electrodeposition of CoNiP onto polycarbonate templates. X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy confirmed the quality of the fabricated nanowires. Magnetic measurements and theoretical analysis revealed that the magnetization reversal and magnetic anisotropy were significantly influenced by varying of the diameters of the nanowires. There existed a critical wire diameter (dc ≈ 276 nm), below which the magnetization reversal occurred via a coherent rotation mode, and above which the magnetization reversal occurred via a curling rotation mode. The easy axis of the magnetization tended to change in direction from parallel to perpendicular with respect to the wire axis as the wire diameter exceeded dc ≈ 276 nm. With increasing wire diameter, the coercive field (Hc) and the remanent to saturation magnetization ratio (Mr/Ms) were also found to rapidly decrease in the range d = 100–400 nm and gradually decrease for d > 400 nm.

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“…9 Consequently, it has recently become a popular trend to try to control the orientation of hcp c axis ͑i.e., easy axis of the magnetocrystal anisotropy͒ and, hence, the effective anisotropy in Co NWs, for example, by applying a magnetic field during electrodeposition or by modifying the above-mentioned deposition parameters. 6,[10][11][12] In this study, we synthesized ordered and high density ͑10 10 / cm 2 ͒ Co NW arrays utilizing freestanding AAO templates and direct-current ͑dc͒ electrodeposition and investigated their magnetic properties as functions of NW aspect ratio ͑͒ and packing factor ͑or template porosity͒ by analyzing room temperature magnetization curves. ͑We note, however, that no special attention was paid to engineer the crystal structure/texture.͒ It is found that array magnetic properties are determined to a great extent by the magnetostatic interactions between array elements.…”

Section: Introductionmentioning

confidence: 99%

Magnetization behavior of ordered and high density Co nanowire arrays with varying aspect ratio

Kartopu

Yalçın

Es‐Souni

et al. 2008

Journal of Applied Physics

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Densely packed and ordered cobalt nanowire ͑NW͒ arrays with aspect ratios ͑wire length/diameter͒ varying between 5 and 250 have been fabricated via electrodeposition into alumina templates. The wire length and diameter were controlled by monitoring the total deposited charge or by adjusting the template pore size, respectively. It is observed from room temperature magnetization curves that the magnetic properties of a given array is largely dependent on the aspect ratio and packing factor. It is shown that behavior of magnetic NW arrays are governed to a large extent by the magnetostatic interactions between NWs and that magnitude of the interaction field increases not only with NW diameter ͑or packing factor͒ but also with NW length.

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Magnetic behavior of electrodeposited cobalt nanowires using different electrolytic bath acidities

Cited by 22 publications

References 11 publications

Controlled Elaboration and Magnetic Properties of Submicrometric Cobalt Fibers

Controlled Elaboration and Magnetic Properties of Submicrometric Cobalt Fibers

Magnetization Reversal and Magnetic Anisotropy in Ordered CoNiP Nanowire Arrays: Effects of Wire Diameter

Magnetization behavior of ordered and high density Co nanowire arrays with varying aspect ratio

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