2,182 research outputs found
The Chagos Islands cases: the empire strikes back
Good governance requires the accommodation of multiple interests in the cause of decision making. However, undue regard for particular sectional interests can take their toll upon public faith in government administration. Historically, broad conceptions of the good of the commonwealth were employed to outweigh the interests of groups that resisted colonisation. In the decision making of the British Empire, the standard approach for justifying the marginalisation of the interests of colonised groups was that they were uncivilised and that particular hardships were the price to be paid for bringing to them the imperial dividend of industrial society. It is widely assumed that with the dismantling of the British Empire, such impulses and their accompanying jurisprudence became a thing of the past. Even as decolonisation proceeded apace after the Second World War, however, the United Kingdom maintained control of strategically important islands with a view towards sustaining its global role. In an infamous example from this twilight period of empire, in the 1960s imperial interests were used to justify the expulsion of the Chagos islanders from the British Indian Ocean Territory (BIOT). Into the twenty-first century, this forced elision of the UK’s interests with the imperial “common good” continues to take centre stage in courtroom battles over the islanders’ rights, being cited before domestic and international tribunals in order to maintain the Chagossians’ exclusion from their homeland. This article considers the new jurisprudence of imperialism which has emerged in a string of decisions which have continued to marginalise the Chagossians’ interests
Negative tunneling magnetoresistance by canted magnetization in MgO/NiO tunnel barriers
The influence of insertion of an ultra-thin NiO layer between the MgO barrier
and ferromagnetic electrode in magnetic tunnel junctions has been investigated
by measuring the tunneling magnetoresistance and the X-ray magnetic circular
dichroism (XMCD). The magnetoresistance shows a high asymmetry with respect to
bias voltage, giving rise to a negative value of -16% at 2.8 K. We attribute
this to the formation of non-collinear spin structures in the NiO layer as
observed by XMCD. The magnetic moments of the interface Ni atoms tilt from the
easy axis due to exchange interaction and the tilting angle decreases with
increasing the NiO thickness. The experimental observations are further support
by non-collinear spin density functional theory
Assisted extraction of the energy level spacings and lever arms in direct current bias measurements of one-dimensional quantum wires, using an image recognition routine
A multiplexer technique is used to individually measure an array of 256 split gates on a single
GaAs/AlGaAs heterostructure. This results in the generation of large volumes of data, which
requires the development of automated data analysis routines. An algorithm is developed to find
the spacing between discrete energy levels, which form due to transverse confinement from the split
gate. The lever arm, which relates split gate voltage to energy, is also found from the measured
data. This reduces the time spent on the analysis. Comparison with estimates obtained visually
show that the algorithm returns reliable results for subband spacing of split gates measured at
1:4 K. The routine is also used to assess DC bias spectroscopy measurements at lower temperatures
(50 mK). This technique is versatile and can be extended to other types of measurements. For
example, it is used to extract the magnetic field at which Zeeman-split 1D subbands cross one
another.This work was supported by the Engineering and Physical Sciences Research Council grant No. EP/IO14268/1.This is the accepted manuscript. The final version is available from AIP at http://scitation.aip.org/content/aip/journal/jap/117/1/10.1063/1.4905484
First-Principles Study on Structural Properties of GeO and SiO under Compression and Expansion Pressure
The detailed analysis of the structural variations of three GeO and
SiO polymorphs (-quartz, -cristobalite, and rutile) under
compression and expansion pressure is reported. First-principles total-energy
calculations reveal that the rutile structure is the most stable phase among
the phases of GeO, while SiO preferentially forms quartz. GeO
tetrahedras of quartz and cristobalite GeO phases at the equilibrium volume
are more significantly distorted than those of SiO. Moreover, in the case
of quartz GeO and cristobalite GeO, all O-Ge-O bond angles vary when
the volume of the GeO bulk changes from the equilibrium point, which causes
further deformation of tetrahedra. In contrast, the tilt angle formed by
Si-O-Si in SiO markedly changes. This flexibility of the O-Ge-O bonds
reduces the stress at the Ge/GeO interface due to the lattice-constant
mismatch and results in the low defective interface observed in the experiments
[Matsubara \textit{et al.}: Appl. Phys. Lett. \textbf{93} (2008) 032104; Hosoi
\textit{et al.}: Appl. Phys. Lett. \textbf{94} (2009) 202112].Comment: 15 pages, 5 figures and 2 table
Statistical study of conductance properties in one-dimensional quantum wires focusing on the 0.7 anomaly
The properties of conductance in one-dimensional (1D) quantum wires are
statistically investigated using an array of 256 lithographically-identical
split gates, fabricated on a GaAs/AlGaAs heterostructure. All the split gates
are measured during a single cooldown under the same conditions. Electron
many-body effects give rise to an anomalous feature in the conductance of a
one-dimensional quantum wire, known as the `0.7 structure' (or `0.7 anomaly').
To handle the large data set, a method of automatically estimating the
conductance value of the 0.7 structure is developed. Large differences are
observed in the strength and value of the 0.7 structure [from to
], despite the constant temperature and identical device
design. Variations in the 1D potential profile are quantified by estimating the
curvature of the barrier in the direction of electron transport, following a
saddle-point model. The 0.7 structure appears to be highly sensitive to the
specific confining potential within individual devices.This is the author's accepted manuscript. The final version is published by ACS in Physical Review B and can be found here: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.045426
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