Templated Assembly of Magnetic Cobalt Nanowire Arrays

Srivastava, Akhilesh Kumar; Singh, Ramayan; Sampson, Karen; Singh, Vijay Pratap; Ramanujan, R.V.

doi:10.1007/s11661-007-9096-7

Cited by 27 publications

(17 citation statements)

References 31 publications

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“…Figure 4b shows that for a field parallel to the tube the coercivity H c ) 824 Oe and for the perpendicular field H c is 123 Oe. This very high coercivity observed for the field parallel to the tube (highest reported value for cobalt wire system of the same diameter, ∼150 nm) 10,19,21,22 indicates that easy axis of magnetization is parallel to the tube axis. Perfect ordering and defect free end surfaces may be the reasons for the exhibition of high coercivity in these one-dimensional structures.…”

Section: Resultsmentioning

confidence: 86%

Synthesis of High Coercivity Cobalt Nanotubes with Acetate Precursors and Elucidation of the Mechanism of Growth

et al. 2008

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Cobalt nanotubes (CoNTs) with very high longitudinal coercivity were prepared by electrodeposition of cobalt acetate for the first time by using anodized alumina (AAO) template. They were then characterized with X-ray diffraction (XRD), a field emission scanning electron microscope (FESEM), and a transmission electron microscope (TEM). Formation of a highly ordered hexagonal cobalt phase is observed. Room temperature SQUID (superconducting quantum interference device) magnetometer measurements indicate that the easy axis of magnetization is parallel to the nanotube axis. These CoNTs exhibit very high longitudinal coercivity of ∼820 Oe. A very high intertubular interaction resulting from magnetostatic dipolar interaction between nanotubes is observed. Thick-walled nanotubes were also fabricated by using cobalt acetate tetrahydrate precursors. A plausible mechanism for the formation of CoNTs based on mobility assisted growth is proposed. The role of the hydration layer and the mobility of metal ions are elucidated in the case of the growth mechanism of one-dimensional geometry.

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Section: Resultsmentioning

confidence: 86%

Synthesis of High Coercivity Cobalt Nanotubes with Acetate Precursors and Elucidation of the Mechanism of Growth

et al. 2008

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“…Magnetic nanowires are interesting nanostructures not only from basic research viewpoints but also because of their applications in data storage [1,2], in gas [3] and acoustic [4] sensor technologies and in modern logic and spintronic devices [5,6].…”

Section: Introductionmentioning

confidence: 99%

Magnetic hysteresis in small-grained Co Pd1− nanowire arrays

Viqueira

López

Urreta

et al. 2015

Journal of Magnetism and Magnetic Materials

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a b s t r a c tCo-Pd nanowires with small grain size are fabricated by AC electrodeposition into hexagonally ordered alumina pores, 20-35 nm in diameter and about 1 mm long. The effects of the alloy composition, the nanowire diameter and the grain size on the hysteresis properties are considered. X-ray diffraction indicates that the nanowires are single phase, a fcc Co-Pd solid solution; electron microscopy results show that they are polycrystalline, with randomly oriented grains (7-12 nm), smaller than the wire diameter. Nanowire arrays are ferromagnetic, with an easy magnetization axis parallel to the nanowire long axis. Both, the coercive field and the loop squareness monotonously increase with the Co content and with the grain size, but no clear correlation with the wire diameter is found. The Co and Co-rich nanowire arrays exhibit coercive fields and reduced remanence values quite insensitive to temperature in the range 4 K-300 K; on the contrary, in Pd-rich nanowires both magnitudes are smaller and they largely increase during cooling below 100 K. These behaviors are systematized by considering the strong dependences displayed by the magneto-crystalline anisotropy and the saturation magnetostriction on composition and temperature. At low temperatures the effective anisotropy value and the domain-wall width to grain size ratio drastically change, promoting less cooperative and harder nucleation modes.

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“…Thus, magnetic nanowires have provided a highly successful test ground for understanding the microscopic mechanisms that determine macroscopically important parameters in the different applications [4,5]. The development of ferromagnetic nanowire arrays has revealed various unusual properties relevant to applications in high density data storage devices and in bioengineering applications [6]. Various efforts to fabricate one-dimensional, two-dimensional, and three-dimensional nanostructures have been made using conventional lithography, nanosphere lithography, di-block copolymers template, and anodic aluminum oxide (AAO) templates [6,7,8,9].…”

Section: Introductionmentioning

confidence: 99%

“…The development of ferromagnetic nanowire arrays has revealed various unusual properties relevant to applications in high density data storage devices and in bioengineering applications [6]. Various efforts to fabricate one-dimensional, two-dimensional, and three-dimensional nanostructures have been made using conventional lithography, nanosphere lithography, di-block copolymers template, and anodic aluminum oxide (AAO) templates [6,7,8,9]. The aim of this research is to examine whether there is a compensation point in a ferrimagnetic core/shell nanowire with different single-ion anisotropies in the longitudinal field.…”

Section: Introductionmentioning

confidence: 99%

Effects of Anisotropy and Longitudinal Field on a Ferrimagnetic Nanowire

Mohamad

Hamade

2015

ILCPA

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A ferrimagnetic nanowire consists of the spin-1/2 core and spin-1 outer shell has been studied. The general formula for the temperature dependence of the longitudinal magnetization of the system is given. The ferrimagnetic core-shell nanowire system exhibits two and three compensation points when the temperature of the system is changed at fixed values of the anisotropy of shell sublattice and longitudinal field, respectively. The competition among the exchange coupling between the outer shell and core, the outer shell coupling, the anisotropy, the applied field, and the temperature has a considerable effect on the characteristic of magnetic properties in a two-dimensional nanowire system.

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Templated Assembly of Magnetic Cobalt Nanowire Arrays

Cited by 27 publications

References 31 publications

Synthesis of High Coercivity Cobalt Nanotubes with Acetate Precursors and Elucidation of the Mechanism of Growth

Synthesis of High Coercivity Cobalt Nanotubes with Acetate Precursors and Elucidation of the Mechanism of Growth

Magnetic hysteresis in small-grained Co Pd1− nanowire arrays

Effects of Anisotropy and Longitudinal Field on a Ferrimagnetic Nanowire

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