1,299 research outputs found
'It’s the Political, Stupid’: National versus Transnational Perspectives on Democratisation in Iraq
Enhanced spin accumulation at room temperature in graphene spin valves with amorphous carbon interfacial layers
We demonstrate a large enhancement of the spin accumulation in monolayer
graphene following electron-beam induced deposition of an amorphous carbon
layer at the ferromagnet-graphene interface. The enhancement is 10^4-fold when
graphene is deposited onto poly(methyl metacrylate) (PMMA) and exposed with
sufficient electron-beam dose to cross-link the PMMA, and 10^3-fold when
graphene is deposited directly onto SiO2 and exposed with identical dose. We
attribute the difference to a more efficient carbon deposition in the former
case due to an increase in the presence of compounds containing carbon, which
are released by the PMMA. The amorphous carbon interface can sustain very large
current densities without degrading, which leads to very large spin
accumulations exceeding 500 microeVs at room temperature
Uncompensated magnetization and exchange-bias field in LaSrMnO/YMnO bilayers: The influence of the ferromagnetic layer
We studied the magnetic behavior of bilayers of multiferroic and nominally
antiferromagnetic o-YMnO (375~nm thick) and ferromagnetic
LaSrMnO and LaCaMnO (nm), in particular the vertical magnetization shift and exchange
bias field for different thickness and magnetic dilution of the
ferromagnetic layer at different temperatures and cooling fields. We have found
very large shifts equivalent to up to 100\% of the saturation value of
the o-YMO layer alone. The overall behavior indicates that the properties of
the ferromagnetic layer contribute substantially to the shift and that
this does not correlate straightforwardly with the measured exchange bias field
.Comment: 10 figures, 8 page
Flexibility versus Inflexibility: discursive discrepancy in US democracy promotion and anti-corruption policies
On simulation in automata networks
An automata network is a finite graph where each node holds a state from some
finite alphabet and is equipped with an update function that changes its state
according to the configuration of neighboring states. More concisely, it is
given by a finite map . In this paper we study how some
(sets of) automata networks can be simulated by some other (set of) automata
networks with prescribed update mode or interaction graph. Our contributions
are the following. For non-Boolean alphabets and for any network size, there
are intrinsically non-sequential transformations (i.e. that can not be obtained
as composition of sequential updates of some network). Moreover there is no
universal automaton network that can produce all non-bijective functions via
compositions of asynchronous updates. On the other hand, we show that there are
universal automata networks for sequential updates if one is allowed to use a
larger alphabet and then use either projection onto or restriction to the
original alphabet. We also characterize the set of functions that are generated
by non-bijective sequential updates. Following Tchuente, we characterize the
interaction graphs whose semigroup of transformations is the full semigroup
of transformations on , and we show that they are the same if we force
either sequential updates only, or all asynchronous updates
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