Magnetic properties of arrays of nanowires: Anisotropy, interactions, and reversal modes

Lavín, R.; Denardin, Juliano C.; Espejo, A. P.; Gómez, H.

doi:10.1063/1.3350905

Cited by 32 publications

(27 citation statements)

References 21 publications

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“…The thermal dependence of anisotropies with different easy axis can lead to a change of magnetization easy axis with temperature as has been recently reported for some Co nanowire arrays [38,54,56]. In the present case, according to Eq.…”

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confidence: 71%

Magnetization reversal in Co‐base nanowire arrays

Vázquez

Vivas

2011

Physica Status Solidi (b)

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The magnetic behaviour of ordered arrays of magnetic nanowires is controlled by the combined action of anisotropy energy terms determined by geometrical shape, crystalline structure and magnetostriction, as well as by the magnetostatic interactions among them. A number of works have been reported on the role of magnetostatic interaction in arrays of nanowires, sometimes focusing on nanowires with vanishing crystalline and magnetostrictive energy terms. Here, in turn we are interested in Co‐base nanowires whose magnetocrystalline anisotropy plays a very important role. Arrays of Co‐base nanowires offer novel, sometimes unexpected behaviour that is not fully understood. Such results are connected to their magnetocrystalline anisotropy, and to their complex magnetization reversal mode. Arrays of Co and Co‐base nanowires have been fabricated by template‐assisted method, by electroplating into highly ordered self‐assembled pores of nanoporous alumina membranes. Their hcp or fcc crystal structure is confirmed to depend on length of nanowires as well as on the presence of selected elements in the composition. The magnetic behaviour of these arrays has been experimentally investigated as a function of (i) geometry (e.g. diameter and, particularly short length) and (ii) composition (e.g. adding Ni or Pd). A complementary study on its temperature dependence reveals the nature of the dominant anisotropy, while the angular dependence of hysteresis loops (e.g. coercivity and remanence) enables a deeper analysis of the magnetization reversal process. Micromagnetic reversal modes are reviewed and modelling and simulations procedures introduced. Complex rotational mechanisms are concluded to be responsible for the reversal process following micromagnetic modes distinct from those pure classically established. SEM image of an array of Co‐base nanowires.

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confidence: 71%

Magnetization reversal in Co‐base nanowire arrays

Vázquez

Vivas

2011

Physica Status Solidi (b)

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“…Previous works reported analytical calculations of the magnetic reversal modes [coherent (C) magnetization rotation, and transverse (T) and vortex-like (V) domain walls] that are energetically more favorable for high aspect ratio NWs and NTs. 8,[13][14][15]20,27,[38][39][40] For analytical calculations it is important to define the parameter b ¼ d i =d, where d i and d are the NT inner and outer diameters, respectively, (Fig. 5).…”

Section: B Magnetization Reversalmentioning

confidence: 99%

Magnetic interactions and reversal mechanisms in Co nanowire and nanotube arrays

Proença¹,

Sousa

Escrig

et al. 2013

Journal of Applied Physics

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Ordered hexagonal arrays of Co nanowires (NWs) and nanotubes (NTs), with diameters between 40 and 65 nm, were prepared by potentiostatic electrodeposition into suitably modified nanoporous alumina templates. The geometrical parameters of the NW/NT arrays were tuned by the pore etching process and deposition conditions. The magnetic interactions between NWs/NTs with different diameters were studied using first-order reversal curves (FORCs). From a quantitative analysis of the FORC measurements, we are able to obtain the profiles of the magnetic interactions and the coercive field distributions. In both NW and NT arrays, the magnetic interactions were found to increase with the diameter of the NWs/NTs, exhibiting higher values for NW arrays. A comparative study of the magnetization reversal processes was also performed by analyzing the angular dependence of the coercivity and correlating the experimental data with theoretical calculations based on a simple analytical model. The magnetization in the NW arrays is found to reverse by the nucleation and propagation of a transverse-like domain wall; on the other hand, for the NT arrays a non-monotonic behavior occurs above a diameter of $50 nm, revealing a transition between the vortex and transverse reversal modes. V C 2013 American Institute of Physics. [http://dx

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“…They resemble one-dimensional columnar parallel chains of magnetic nanoparticles under different spatial arrangement (square, hexagonal) and different lengths along the X-axis. The study of such type of structures is at the center of much research nowadays for the basic study of the competition between the enhanced anisotropy and magnetostatic interactions [31][32][33][34][35]. The magnetic properties of such chain-like systems exhibit a good analogy to the behavior of ferromagnetic nanowires [36].…”

Section: Spatial Arrangementmentioning

confidence: 99%

Superparamagnetism and Monte Carlo Simulations

Serantes¹

2012

TOSURSJ

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Abstract:We summarize the basic concepts beneath the idea of superparamagnetism and introduce the Monte Carlo (MC) method as a powerful tool for studying superparamagnetic (SPM) properties. Starting with the description of the physical features of the single-domain SPM entities, we concentrate on their special magnetic properties as a function of time, temperature, and applied magnetic field. Then, we give a general approach to the use of a MC technique for studying SPM properties, focusing on the use of the Metropolis algorithm and discussing the importance of the choice of the MC steps in the simulations.

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Magnetic properties of arrays of nanowires: Anisotropy, interactions, and reversal modes

Cited by 32 publications

References 21 publications

Magnetization reversal in Co‐base nanowire arrays

Magnetization reversal in Co‐base nanowire arrays

Magnetic interactions and reversal mechanisms in Co nanowire and nanotube arrays

Superparamagnetism and Monte Carlo Simulations

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