1,619 research outputs found
Selective spin transport through a quantum heterostructure: Transfer matrix method
In the present work we propose that a one-dimensional quantum heterostructure
composed of magnetic and non-magnetic atomic sites can be utilized as a spin
filter for a wide range of applied bias voltage. A simple tight-binding
framework is given to describe the conducting junction where the
heterostructure is coupled to two semi-infinite one-dimensional non-magnetic
electrodes. Based on transfer matrix method all the calculations are performed
numerically which describe two-terminal spin dependent transmission probability
along with junction current through the wire. Our detailed analysis may provide
fundamental aspects of selective spin transport phenomena in one-dimensional
heterostructures at nano-scale level.Comment: 12 pages, 15 figures (Accepted for Publication in: International
Journal of Modern Physics B
Resonant Photoelectron Diffraction with circularly polarized light
Resonant angle scanned x-ray photoelectron diffraction (RXPD) allows the
determination of the atomic and magnetic structure of surfaces and interfaces.
For the case of magnetized nickel the resonant L2 excitation with circularly
polarized light yields electrons with a dichroic signature from which the
dipolar part may be retrieved. The corresponding L2MM and L3MM Auger electrons
carry different angular momenta since their source waves rotate the dichroic
dipole in the electron emission patterns by distinct angles
Intercalation of graphene on SiC(0001) via ion-implantation
Electronic devices based on graphene technology are catching on rapidly and
the ability to engineer graphene properties at the nanoscale is becoming, more
than ever, indispensable. Here, we present a new procedure of graphene
functionalization on SiC(0001) that paves the way towards the fabrication of
complex graphene electronic chips. The procedure resides on the well-known
ion-implantation technique. The efficiency of the working principle is
demonstrated by the intercalation of the epitaxial graphene layer on SiC(0001)
with Bi atoms, which was not possible following standard procedures. Our
results put forward the ion-beam lithography to nanostructure and functionalize
desired graphene chips
Observation of Spin-glass-like Behavior in SrRuO3 Epitaxial Thin Films
We report the observation of spin-glass-like behavior and strong magnetic
anisotropy in extremely smooth (~1-3 \AA) roughness) epitaxial (110) and (010)
SrRuO3 thin films. The easy axis of magnetization is always perpendicular to
the plane of the film (unidirectional) irrespective of crystallographic
orientation. An attempt has been made to understand the nature and origin of
spin-glass behavior, which fits well with Heisenberg model.Comment: 5 pages, 5 Figure
On rationality of the intersection points of a line with a plane quartic
We study the rationality of the intersection points of certain lines and
smooth plane quartics C defined over F_q. For q \geq 127, we prove the
existence of a line such that the intersection points with C are all rational.
Using another approach, we further prove the existence of a tangent line with
the same property as soon as the characteristic of F_q is different from 2 and
q \geq 66^2+1. Finally, we study the probability of the existence of a rational
flex on C and exhibit a curious behavior when the characteristic of F_q is
equal to 3.Comment: 17 pages. Theorem 2 now includes the characteristic 2 case;
Conjecture 1 from the previous version is proved wron
360 degree domain wall generation in the soft layer of magnetic tunnel junctions
High spatial resolution X-ray photo-emission electron microscopy technique
has been used to study the influence of the dipolar coupling taking place
between the NiFe and the Co ferromagnetic electrodes of micron sized,
elliptical shaped magnetic tunnel junctions. The chemical selectivity of this
technique allows to observe independently the magnetic domain structure in each
ferromagnetic electrode. The combination of this powerful imaging technique
with micromagnetic simulations allows to evidence that a 360 degree domain wall
can be stabilized in the NiFe soft layer. In this letter, we discuss the origin
and the formation conditions of those 360 degree domain walls evidenced
experimentally and numerically
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