105,594 research outputs found
Effects of ion irradiation on conductivity of CrSi_2 thin films
Electrical resistivity measurements are used to study damage in CrSi_2 thin films induced by Ne, Ar, or Xe ion irradiation over a fluence range of 10^(10)–10^(15) ions cm^(−2). Irradiation produces a factor of 5–12 increase in film conductivity at the higher fluences. The influence of defect generation and recombination is evident. We speculate that formation of a compound defect is a dominant factor enhancing film conductivity. A temperature dependence at low fluences is reported and tentatively identified
Controlling spin in an electronic interferometer with spin-active interfaces
We consider electronic current transport through a ballistic one-dimensional
quantum wire connected to two ferromagnetic leads. We study the effects of the
spin-dependence of interfacial phase shifts (SDIPS) acquired by electrons upon
scattering at the boundaries of the wire. The SDIPS produces a spin splitting
of the wire resonant energies which is tunable with the gate voltage and the
angle between the ferromagnetic polarizations. This property could be used for
manipulating spins. In particular, it leads to a giant magnetoresistance effect
with a sign tunable with the gate voltage and the magnetic field applied to the
wire.Comment: 5 pages, 3 figures. to be published in Europhysics Letter
Coexistence of Localized and Extended States in Disordered Systems
It is commonly believed that Anderson localized states and extended states do
not coexist at the same energy. Here we propose a simple mechanism to achieve
the coexistence of localized and extended states in a band in a class of
disordered quasi-1D and quasi-2D systems. The systems are partially disordered
in a way that a band of extended states always exists, not affected by the
randomness, whereas the states in all other bands become localized. The
extended states can overlap with the localized states both in energy and in
space, achieving the aforementioned coexistence. We demonstrate such
coexistence in disordered multi-chain and multi-layer systems.Comment: 5 pages, 3 figure
A probabilistic model checking approach to analysing reliability, availability, and maintainability of a single satellite system
Satellites now form a core component for space
based systems such as GPS and GLONAS which provide
location and timing information for a variety of uses. Such
satellites are designed to operate in-orbit and have lifetimes of
10 years or more. Reliability, availability and maintainability
(RAM) analysis of these systems has been indispensable in
the design phase of satellites in order to achieve minimum
failures or to increase mean time between failures (MTBF)
and thus to plan maintainability strategies, optimise reliability
and maximise availability. In this paper, we present formal
modelling of a single satellite and logical specification of
its reliability, availability and maintainability properties. The
probabilistic model checker PRISM has been used to perform
automated quantitative analyses of these properties
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