168 research outputs found
Spin Relaxation in Graphene with self-assembled Cobalt Porphyrin Molecules
In graphene spintronics, interaction of localized magnetic moments with the
electron spins paves a new way to explore the underlying spin relaxation
mechanism. A self-assembled layer of organic cobalt-porphyrin (CoPP) molecules
on graphene provides a desired platform for such studies via the magnetic
moments of porphyrin-bound cobalt atoms. In this work a study of spin transport
properties of graphene spin-valve devices functionalized with such CoPP
molecules as a function of temperature via non-local spin-valve and Hanle spin
precession measurements is reported. For the functionalized (molecular)
devices, we observe a slight decrease in the spin relaxation time ({\tau}s),
which could be an indication of enhanced spin-flip scattering of the electron
spins in graphene in the presence of the molecular magnetic moments. The effect
of the molecular layer is masked for low quality samples (low mobility),
possibly due to dominance of Elliot-Yafet (EY) type spin relaxation mechanisms
Context based configuration management system
A computer-based system for configuring and displaying information on changes in, and present status of, a collection of events associated with a project. Classes of icons for decision events, configurations and feedback mechanisms, and time lines (sequential and/or simultaneous) for related events are displayed. Metadata for each icon in each class is displayed by choosing and activating the corresponding icon. Access control (viewing, reading, writing, editing, deleting, etc.) is optionally imposed for metadata and other displayed information
Monocular Depth Estimation through Virtual-world Supervision and Real-world SfM Self-Supervision
Depth information is essential for on-board perception in autonomous driving
and driver assistance. Monocular depth estimation (MDE) is very appealing since
it allows for appearance and depth being on direct pixelwise correspondence
without further calibration. Best MDE models are based on Convolutional Neural
Networks (CNNs) trained in a supervised manner, i.e., assuming pixelwise ground
truth (GT). Usually, this GT is acquired at training time through a calibrated
multi-modal suite of sensors. However, also using only a monocular system at
training time is cheaper and more scalable. This is possible by relying on
structure-from-motion (SfM) principles to generate self-supervision.
Nevertheless, problems of camouflaged objects, visibility changes,
static-camera intervals, textureless areas, and scale ambiguity, diminish the
usefulness of such self-supervision. In this paper, we perform monocular depth
estimation by virtual-world supervision (MonoDEVS) and real-world SfM
self-supervision. We compensate the SfM self-supervision limitations by
leveraging virtual-world images with accurate semantic and depth supervision
and addressing the virtual-to-real domain gap. Our MonoDEVSNet outperforms
previous MDE CNNs trained on monocular and even stereo sequences.Comment: Published in IEEE-Transactions on Intelligent Transportation Systems,
2021 14 pages, 10 figure
Project management tool
A system for managing a project that includes multiple tasks and a plurality of workers. Input information includes characterizations based upon a human model, a team model and a product model. Periodic reports, such as a monthly report, a task plan report, a budget report and a risk management report, are generated and made available for display or further analysis. An extensible database allows searching for information based upon context and upon content
Nonlinear analog spintronics with van der Waals heterostructures
The current generation of spintronic devices, which use electron-spin relies
on linear operations for spin-injection, transport and detection processes. The
existence of nonlinearity in a spintronic device is indispensable for
spin-based complex signal processing operations. Here we for the first time
demonstrate the presence of electron-spin dependent nonlinearity in a
spintronic device, and measure up to 4th harmonic spin-signals via nonlocal
spin-valve and Hanle spin-precession measurements. We demonstrate its
application for analog signal processing over pure spin-signals such as
amplitude modulation and heterodyne detection operations which require
nonlinearity as an essential element. Furthermore, we show that the presence of
nonlinearity in the spin-signal has an amplifying effect on the
energy-dependent conductivity induced nonlinear spin-to-charge conversion
effect. The interaction of the two spin-dependent nonlinear effects in the spin
transport channel leads to a highly efficient detection of the spin-signal
without using ferromagnets. These effects are measured both at 4K and room
temperature, and are suitable for their applications as nonlinear circuit
elements in the fields of advanced-spintronics and spin-based neuromorphic
computing.Comment: 14 pages, 8 figure
Bias dependent spin injection into graphene on YIG through bilayer hBN tunnel barriers
We study the spin injection efficiency into single and bilayer graphene on
the ferrimagnetic insulator Yttrium-Iron-Garnet (YIG) through an exfoliated
tunnel barrier of bilayer hexagonal boron nitride (hBN). The contacts of two
samples yield a resistance-area product between 5 and 30 km.
Depending on an applied DC bias current, the magnitude of the non-local spin
signal can be increased or suppressed below the noise level. The spin injection
efficiency reaches values from -60% to +25%. The results are confirmed with
both spin valve and spin precession measurements. The proximity induced
exchange field is found in sample A to be (85 30) mT and in sample B
close to the detection limit. Our results show that the exceptional spin
injection properties of bilayer hBN tunnel barriers reported by Gurram et al.
are not limited to fully encapsulated graphene systems but are also valid in
graphene/YIG devices. This further emphasizes the versatility of bilayer hBN as
an efficient and reliable tunnel barrier for graphene spintronics.Comment: 9 pages, 6 figures, 5 supplementary figure
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