595 research outputs found
Magnetic structure of domain walls confined in a nano-oxide layer
In the recent years, a spin-valve was developed with a current-confined-path
structure consisting of a non-oxide-layer (NOL). We analyze magnetic structures
of the current-confinedpath in the nano-oxide layer sandwiched between
ferromagnetic electrodes and clarify the dependency of the magnetic structure
on the shape and size of the current-confined-path. Our results of stiffness
energy density and thermal stability shows that we should fabricate a CPP
spin-valve with narrow current-confinedpaths with large aspect ratio and strong
constriction in order to enhance the MR ratio.Comment: 3 pages, 3 figures, proceedings paper of Intermag 200
Effective Resistance Mismatch and Magnetoresistance of a CPP-GMR system with Current-Confined-Paths
We theoretically study the magnetoresistance of a CPP-GMR system with current
confined paths (CCP) in the framework of Valet-Fert theory. The continuity
equations for charge and spin currents are numerically solved with the
three-dimensional CCP geometry by use of finite element method. It is confirmed
that the MR ratio is enhanced by the CCP structure, which is consistent with
the experimental results. Moreover, we find that there exists a certain contact
width which maximize the MR ratio. We show that the contact width which
maximize the MR ratio is well described by the effective resistance matching.Comment: 4 pages, 4 figure
Base manifolds for fibrations of projective irreducible symplectic manifolds
Given a projective irreducible symplectic manifold of dimension , a
projective manifold and a surjective holomorphic map with
connected fibers of positive dimension, we prove that is biholomorphic to
the projective space of dimension . The proof is obtained by exploiting two
geometric structures at general points of : the affine structure arising
from the action variables of the Lagrangian fibration and the structure
defined by the variety of minimal rational tangents on the Fano manifold
Atomic scale localization of Kohn-Sham wavefunction at SiO2/4H-SiC interface under electric field, deviating from envelope function by effective mass approximation
To clarify the cause of the low channel conductivity at the SiO2/4H-SiC
interface, the wavefunction at the SiC conduction band minimum was calculated
using density functional theory under an applied electric field. We found that
the wavefunction for a 4H-SiC (0001) slab tends to be localized at the cubic
site closest to the interface. Importantly, because the conduction electrons
are distributed closer to the interface (< 5 angstroms) than expected from the
effective mass approximation (EMA), they are more frequently scattered by
interface defects. This is expected to be the reason why the channel
conductivity for the (0001) face is particularly low compared with that for
other faces, such as (11-20). The breakdown of the EMA for the (0001) interface
is related to the long structural periodicity along the [0001] direction in
4H-SiC crystals
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