arXiv subjects

J. Escrig

Publications and source records attributed to J. Escrig.

25 records · Page 2Linked to original sources

arXiv2007

Magnetic properties of bi-phase micro- and nanotubes

The magnetic configurations of bi-phase micro- and nanotubes consisting of a ferromagnetic internal tube, an intermediate non-magnetic spacer, and an external magnetic shell are investigated as a function of their geometry. Based on a continuum approach we obtained analytical expressions for the energy which lead us to obtain phase diagrams giving the relative stability of characteristic internal magnetic configurations of the bi-phase tubes.

cond-mat.mtrl-sci↗

arXiv2007

Vortex core size in interacting cylindrical nanodot arrays

The effect of dipolar interactions among cylindrical nanodots, with a vortex-core magnetic configuration, is analyzed by means of analytical calculations. The cylinders are placed in a N x N square array in two configurations - core oriented parallel to each other and with antiparallel alignment between nearest neighbors. Results comprise the variation in the core radius with the number of interacting dots, the distance between them and dot height. The dipolar interdot coupling leads to a decrease (increase) of the core radius for parallel (antiparallel) arrays.

cond-mat.mtrl-sci↗

arXiv2007

Angular dependence of coercivity in magnetic nanotubes

The nucleation field for infinite magnetic nanotubes, in the case of a magnetic field applied parallel to the long axis of the tubes, is calculated as a function of their geometric parameters and compared with those produced inside the pores of anodic alumina membranes by atomic layer deposition. We also extended this result to the case of an angular dependence. We observed a transition from curling-mode rotation to coherent-mode rotation as a function of the angle in which the external magnetic field is applied. Finally, we observed that the internal radii of the tubes favors the magnetization curling reversal.

cond-mat.soft↗

arXiv2007

Remanence of Ni nanowire arrays: Influence of size and labyrinth magnetic structure

The influence of the macroscopic size of the Ni nanowire array system on their remanence state has been investigated. A simple magnetic phenomenological model has been developed to obtain the remanence as a function of the magnetostatic interactions in the array. We observe that, due to the long range of the dipolar interactions between the wires, the size of the sample strongly influence the remanence of the array. On the other hand, the magnetic state of nanowires has been studied by variable field magnetic force microscopy for different remanent states. The distribution of nanowires with the magnetization in up or down directions and the subsequent remanent magnetization has been deduced from the magnetic images. The existence of two short-range magnetic orderings with similar energies can explain the typical labyrinth pattern observed in magnetic force microscopy images of the nanowire arrays.

cond-mat.mtrl-sci↗

arXiv2006

A detailed analysis of dipolar interactions and analytical approximations in arrays of magnetic nanowires

The investigation of the role of interactions in magnetic wire arrays is complex and often subject to strong simplifications. In this paper we obtained analytical expressions for the magnetostatic interactions between wires and investigate the range of validity of dipole-dipole, first order and second order approximations. We also analyze the extension of the interwire magnetostatic interactions in a sample and found that the number of wires required to reach energy convergence in the array strongly depends on the relative magnetic orientation between the wires.

cond-mat.mtrl-sci↗

arXiv2006

Reversal modes in magnetic nanotubes

The magnetic switching of ferromagnetic nanotubes is investigated as a function of their geometry. Two independent methods are used: Numerical simulations and analytical calculations. It is found that for long tubes the reversal of magnetization is achieved by two mechanism: The propagation of a transverse or a vortex domain wall depending on the internal and external radii of the tube.

cond-mat.mtrl-sci↗

arXiv2006

Stability of magnetic configurations in nanorings

The relative stability of the vortex, onion and ferromagnetic phases in nanorings is examined as a function of the ring geometry. Total energy calculations are carried out analytically, based on simple models for each configuration. Results are summarized by phase diagrams, which might be used as a guide to the production of rings with specific magnetic properties.

cond-mat.mtrl-sci↗