Now showing items 1-3 of 3

Domain wall propagation tuning in magnetic nanowires through geometric modulation

Costa Arzuza, Luis Carlos; López Ruiz, Román; Salazar Aravena, Diego; Knobel, Marcelo; Beron, Fanny; Pirota, Kleber Roberto (Journal of Magnetism and Magnetic Materials, 2017-01-25)

The magnetic behavior of nickel modulated nanowires embedded in porous alumina membranes is investigated. Their diameters exhibit a sharp transition between below (35 nm) and above (52 nm) the theoretical limit for transverse ...
Effective demagnetizing tensors in arrays of magnetic nanopillars

Mendoza Zelis, P; Vega, Víctor V; Prida, V M; Costa Arzuza, Luis Carlos; Beron, Fanny; Pirota, Kleber Roberto; Lopez Ruiz, Roman; Sanchez, Francisco Homero (Physical Review B, 2017-11-21)

A model describing the effect of magnetic dipolar interactions on the susceptibility of magnetic nanopillars is presented. It is an extension of a recently reported model for three-dimensional randomlike dispersions of ...
Synthesis and magnetic properties of cobalt-iron/cobalt-ferrite soft/hard magnetic core/shell nanowires

Londoño Calderón, Cesar Leandro; Moscoso Londoño, Oscar; Muraca, Diego; Costa Arzuza, Luis Carlos; Carvalho, Peterson; Pirota, Kleber Roberto; Knobel, Marcelo; Pampillo, Laura Gabriela; Martínez García, Ricardo (Nanotechnology, 2017)

A straightforward method for the synthesis of CoFe2.7/CoFe2O4 core/shell nanowires is described. The proposed method starts with a conventional pulsed electrodeposition procedure on alumina nanoporous template. The obtained ...

Envíos recientes

Domain wall propagation tuning in magnetic nanowires through geometric modulation
...
Costa Arzuza, Luis Carlos | 2017-01-25

The magnetic behavior of nickel modulated nanowires embedded in porous alumina membranes is investigated. Their diameters exhibit a sharp transition between below (35 nm) and above (52 nm) the theoretical limit for transverse and vortex domain walls. Magnetic hysteresis loops and first-order reversal curves (FORCs) were measured on several ordered nanowire arrays with different wide-narrow segment lengths ratio and compared with those from homogenous nanowires. The experimental magnetic response evidences a rather complex susceptibility behavior for nanowires with modulated diameter. Micromagnetic simulations on isolated and first-neighbors arrays of nanowires show that the domain wall structure, which depends on the segment diameter, suffers a transformation while crossing the diameter modulation, but without any pinning. The experimental array magnetic behavior can be ascribed to a heterogeneous stray field induced by the diameter modulation, yielding a stronger interaction field at the wide extremity than at the narrow one. The results evidence the possibility to control the domain wall propagation and morphology by modulating the lateral aspect of the magnetic entity.

LEER
Effective demagnetizing tensors in arrays of magnetic nanopillars
...
Mendoza Zelis, P | 2017-11-21

A model describing the effect of magnetic dipolar interactions on the susceptibility of magnetic nanopillars is presented. It is an extension of a recently reported model for three-dimensional randomlike dispersions of nearly spherical nanoparticles in equilibrium [Sánchez et al., Phys. Rev. B 95, 134421 (2017)], to well-ordered arrays of nanoparticles out of equilibrium. To test it, a high-quality benchmark consisting of a two-dimensional hexagonal arrangement of quasi-identical parallel nickel nanopillars embedded in a porous alumina template was fabricated. This model is based on an effective demagnetizing tensor, which only depends on a few morphological parameters of the sample, as the nearest-neighbor distance between pillars and the volume fraction of pillars in the specimen. It allows us to obtain the nanopillar intrinsic susceptibility tensor from the magnetic response of the nanopillar ensemble. The values of the in-plane and normal-to-plane susceptibility of the sample are successfully predicted by the model. Furthermore, the model reproduces the susceptibility in the applied field direction, measured for different applied field angles. In this way, it provides a simple and accurate treatment to account for the complex magnetic effects produced by dipolar interactions.

LEER
Synthesis and magnetic properties of cobalt-iron/cobalt-ferrite soft/hard magnetic core/shell nanowires
...
Londoño Calderón, Cesar Leandro | 2017

A straightforward method for the synthesis of CoFe2.7/CoFe2O4 core/shell nanowires is described. The proposed method starts with a conventional pulsed electrodeposition procedure on alumina nanoporous template. The obtained CoFe2.7 nanowires are released from the template and allowed to oxidize at room conditions over several weeks. The effects of partial oxidation on the structural and magnetic properties were studied by x-ray spectrometry, magnetometry, and scanning and transmission electron microscopy. The results indicate that the final nanowires are composed of 5 nm iron-cobalt alloy nanoparticles. Releasing the nanowires at room conditions promoted surface oxidation of the nanoparticles and created a CoFe2O4 shell spinel-like structure. The shell avoids internal oxidation and promotes the formation of bi-magnetic soft/hard magnetic core/shell nanowires. The magnetic properties of both the initial single-phase CoFe2.7 nanowires and the final core/shell nanowires, reveal that the changes in the properties from the array are due to the oxidation more than effects associated with released processes (disorder and agglomeration).

LEER

Browsing by Author "Costa Arzuza, Luis Carlos"

Domain wall propagation tuning in magnetic nanowires through geometric modulation ﻿

Effective demagnetizing tensors in arrays of magnetic nanopillars ﻿

Synthesis and magnetic properties of cobalt-iron/cobalt-ferrite soft/hard magnetic core/shell nanowires ﻿

Envíos recientes

Domain wall propagation tuning in magnetic nanowires through geometric modulation

Effective demagnetizing tensors in arrays of magnetic nanopillars

Synthesis and magnetic properties of cobalt-iron/cobalt-ferrite soft/hard magnetic core/shell nanowires

Domain wall propagation tuning in magnetic nanowires through geometric modulation

Effective demagnetizing tensors in arrays of magnetic nanopillars

Synthesis and magnetic properties of cobalt-iron/cobalt-ferrite soft/hard magnetic core/shell nanowires