449 research outputs found
Angular dependence of magnetic properties in Ni nanowire arrays
The angular dependence of the remanence and coercivity of Ni nanowire arrays
produced inside the pores of anodic alumina membranes has been studied. By
comparing our analytical calculations with our measurements, we conclude that
the magnetization reversal in this array is driven by means of the nucleation
and propagation of a transverse wall. A simple model based on an adapted
Stoner-Wohlfarth model is used to explain the angular dependence of the
coercivity
Magnetostatic bias in multilayer microwires: theory and experiments
The hysteresis curves of multilayer microwires consisting of a soft magnetic
nucleus, intermediate non-magnetic layers, and an external hard magnetic layer
are investigated. The magnetostatic interaction between magnetic layers is
proved to give rise to an antiferromagnetic-like coupling resulting in a
magnetostatic bias in the hysteresis curves of the soft nucleus. This
magnetostatic biasing effect is investigated in terms of the microwire
geometry. The experimental results are interpreted considering an analytical
model taking into account the magnetostatic interaction between the magnetic
layers.Comment: 6 pages, 7 figure
Scaling relations for magnetic nanoparticles
A detailed investigation of the scaling relations recently proposed by [J.
d'Albuquerque e Castro, D. Altbir, J. C. Retamal, and P. Vargas, Phys. Rev.
Lett. 88, 237202 (2002)] to study the magnetic properties of nanoparticles is
presented. Analytical expressions for the total energy of three characteristic
internal configurations of the particles are obtained, in terms of which the
behavior of the magnetic phase diagram for those particles upon scaling of the
exchange interaction is discussed. The exponent in scaling relations is
shown to be dependent on the geometry of the vortex core, and results for
specific cases are presented.Comment: 6 pages, 4 figure
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
Efficient photovoltaic and electroluminescent perovskite devices
Planar diode structures employing hybrid organic-inorganic methylammonium lead iodide perovskites lead to multifunctional devices exhibiting both a high photovoltaic efficiency and good electroluminescence. The electroluminescence strongly improves at higher current density applied using a pulsed driving method
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