865 research outputs found
Magnetostatics of synthetic ferrimagnet elements
We calculate the magnetostatic energy of synthetic ferrimagnet (SyF)
elements, consisting of two thin ferromagnetic layers coupled
antiferromagnetically through RKKY coupling. We calculate exact formulas as
well as approximate yet accurate ones, which can be used to easily derive
energy barriers and anisotropy fields of SyF. These can be used to evaluate
coercivity, thermal stability and other useful quantities
Universal Relationship Between Giant Magnetoresistance and Anisotropic Magnetoresistance in Spin Valve Multilayers
We measure the giant magnetoresistance (GMR) with the current both parallel
and perpendicular to the direction of the magnetization in the ferromagnetic
(FM) layers and thus probe the anisotropy of the effective mean free paths for
the spin-up and spin-down electrons, seen in the anisotropic magnetoresistance.
We find that the difference of the GMR in the two configurations, when
expressed in terms of the sheet conductance, displays a nearly universal
behavior as a function of GMR. On interpreting the results within the Boltzmann
transport formalism we demonstrate the importance of bulk scattering for GMR.Comment: REVTEX, 2 figure
Impurity induced enhancement of perpendicular magnetic anisotropy in Fe/MgO tunnel junctions
Using first-principles calculations, we investigated the impact of chromium
(Cr) and vanadium (V) impurities on the magnetic anisotropy and spin
polarization in Fe/MgO magnetic tunnel junctions. It is demonstrated using
layer resolved anisotropy calculation technique, that while the impurity near
the interface has a drastic effect in decreasing the perpendicular magnetic
anisotropy (PMA), its position within the bulk allows maintaining high surface
PMA. Moreover, the effective magnetic anisotropy has a strong tendency to go
from in-plane to out-of-plane character as a function of Cr and V concentration
favoring out-of-plane magnetization direction for ~1.5 nm thick Fe layers at
impurity concentrations above 20 %. At the same time, spin polarization is not
affected and even enhanced in most situations favoring an increase of tunnel
magnetoresistance (TMR) values.Comment: 6 pages, 3 figure
Anatomy of perpendicular magnetic anisotropy in Fe/MgO magnetic tunnel junctions: First principles insight
Using first-principles calculations, we elucidate microscopic mechanisms of
perpendicular magnetic anisotropy (PMA)in Fe/MgO magnetic tunnel junctions
through evaluation of orbital and layer resolved contributions into the total
anisotropy value. It is demonstrated that the origin of the large PMA values is
far beyond simply considering the hybridization between Fe-3dd_{yz(xz)}d_{z^2}d_{xy}d_{x^2-y^2}^2$.Comment: 5 pages, 5 figure
Artificial ferroelectricity due to anomalous Hall effect in magnetic tunnel junctions
We theoretically investigated Anomalous Hall Effect (AHE) and Spin Hall
Effect (SHE) transversally to the insulating spacer O, in magnetic tunnel
junctions of the form F/O/F where F are ferromagnetic layers and O represents a
tunnel barrier. We considered the case of purely ballistic (quantum mechanical)
transport, taking into account the assymetric scattering due to spin-orbit
interaction in the tunnel barrier. AHE and SHE in the considered case have a
surface nature due to proximity effect. Their amplitude is in first order of
the scattering potential. This contrasts with ferromagnetic metals wherein
these effect are in second (side-jump scattering) and third (skew scattering)
order on these potentials. The value of AHE voltage in insulating spacer may be
much larger than in metallic ferromagnetic electrodes. For the antiparallel
orientation of the magnetizations in the two F-electrodes, a spontaneous Hall
voltage exists even at zero applied voltage. Therefore an insulating spacer
sandwiched between two ferromagnetic layers can be considered as exhibiting a
spontaneous ferroelectricity
The Dove Real Beauty Campaign: How Does It Wash
This study analyzes the Dove Real Beauty Campaign including branding successes and failures, corporate responsibilities, and the evolution of the brand development and management through a two-way symmetrical model. It analyzes the DRBC from a marketing and public relations perspective as well as a women’s and gender studies perspective. Dove’s Real Beauty Campaign sprung from the idea that all women are beautiful and it sought to change the status quo by showing the natural physical variation embodied by all women and inspire a broader, healthier, more democratic view of beauty. As the power of the Dove Real Beauty initiative appears to be fizzling out with its current diluted advertising, it nonetheless was a groundbreaking, revolutionary campaign that was successful in ushering in a new age of female empowerment. Dove exemplified the advantages, disadvantages, and overwhelming responsibility that came with a “real beauty” social marketing campaign. The study ultimately serves as an educational tool for the fields of marketing, public relations, and women’s and gender studies
Current perpendicular to plane Giant Magnetoresistance (GMR) in laminated nanostructures
We theoretically studied spin dependent electron transport
perpendicular-to-plain (CPP) in magnetic laminated multilayered structures by
using Kubo formalism. We took into account not only bulk scattering, but the
interface resistance due to both specular and diffuse reflection and also spin
conserving and spin-flip processes. It was shown that spin-flip scattering at
interfaces substantially reduces the value of GMR. This can explain the
experimental observations that the CPP GMR ratio for laminated structures only
slightly increases as compared to non-laminated ones despite lamination induces
a significant increase in CPP resistance.Comment: 4 pages, 2 figure
- …