1,946 research outputs found
Spin motive forces and current fluctuations due to Brownian motion of domain walls
We compute the power spectrum of the noise in the current due to spin motive
forces by a fluctuating domain wall. We find that the power spectrum of the
noise in the current is colored, and depends on the Gilbert damping, the spin
transfer torque parameter , and the domain-wall pinning potential and
magnetic anisotropy. We also determine the average current induced by the
thermally-assisted motion of a domain wall that is driven by an external
magnetic field. Our results suggest that measuring the power spectrum of the
noise in the current in the presence of a domain wall may provide a new method
for characterizing the current-to-domain-wall coupling in the system.Comment: Submitted to "Special issue: Caloritronics" in Solid State
Communication
Tips for research recruitment: The views of sexual minority youth
Researchers often experience difficulties recruiting hard-to-reach populations. This is especially so for studies involving those who have been historically stigmatized, such as individuals who challenge heteronormative expectations or people who experience mental ill health. The authors aimed to obtain the views of sexual minority adolescents (n=25) about what encouraged their participation in a research project. The authors used a general inductive approach to analyze interview data. Feedback consisted of 2 main overarching themes: tips and suggestions for future research and appreciate participants’ motivation to get involved in research. Strategies for how recruitment can be optimized for studies involving sexual minority young people are discussed
Spin-transfer mechanism for magnon-drag thermopower
We point out a relation between the dissipative spin-transfer-torque
parameter and the contribution of magnon drag to the thermoelectric
power in conducting ferromagnets. Using this result we estimate in iron
at low temperatures, where magnon drag is believed to be the dominant
contribution to the thermopower. Our results may be used to determine
from magnon-drag-thermopower experiments, or, conversely, to infer the strength
of magnon drag via experiments on spin transfer
Current-driven and field-driven domain walls at nonzero temperature
We present a model for the dynamics of current- and field-driven domain-wall
lines at nonzero temperature. We compute thermally-averaged drift velocities
from the Fokker-Planck equation that describes the nonzero-temperature dynamics
of the domain wall. As special limits of this general description, we describe
rigid domain walls as well as vortex domain walls. In these limits, we
determine also depinning times of the domain wall from an extrinsic pinning
potential. We compare our theory with previous theoretical and experimental
work
When genomic medicine reveals misattributed genetic relationships – the debate about disclosure revisited
This is the author accepted manuscript. The final version is available from Nature Publishing Group via the DOI in this record.Purpose: Accidental discovery of misattributed parentage is an age-old problem in clinical
medicine, but the ability to detect it routinely has increased recently as a result of highthroughput
DNA sequencing technologies coupled with family sequencing studies. Problems
arise at the clinical-research boundary, where policies and consent forms guaranteeing
nondisclosure may conflict with standard clinical care. Methods: To examine the challenges
of managing misattributed parentage within hybrid translational research studies, we use a
case study of a developmentally delayed child with a candidate variant found through a largescale
trio genome sequencing study in which data from unrelated samples is routinely
excluded. Results: We discuss whether genetic parentage should be explicitly confirmed
during clinical validation, thus giving greater weight to the diagnosis according to ACMG
variant interpretation guidelines, and what tensions this approach would create. Conclusion:
We recommend that the possibility of finding and disclosing misattributed parentage should
be addressed during the consent or pre-test counselling process, and that clinical relevance
should determine whether or not to disclose results in the clinic. This proposition has
implications for research governance, and implies that it may not always be possible to
uphold nondisclosure commitments as investigations move from research to clinical care.The authors wish to thank the DDD study (HICF-1009-003) and PAGE project (HICF-R7-
396) for providing inspiration for this paper. MP and the Wellcome Centre for Ethics and
Humanities are supported by a Wellcome Centre Grant (203132/Z/16/Z). AL is supported by
a collaborative award from the Wellcome (208053/Z/17/Z)
Optimizing propagating spin wave spectroscopy
The frequency difference between two oppositely propagating spin waves can be
used to probe several interesting magnetic properties, such as the
Dzyaloshinkii-Moriya interaction (DMI). Propagating spin wave spectroscopy is a
technique that is very sensitive to this frequency difference. Here we show
several elements that are important to optimize devices for such a measurement.
We demonstrate that for wide magnetic strips there is a need for de-embedding.
Additionally, for these wide strips there is a large parasitic antenna-antenna
coupling that obfuscates any spin wave transmission signal, which is remedied
by moving to smaller strips. The conventional antenna design excites spin waves
with two different wave vectors. As the magnetic layers become thinner, the
resulting resonances move closer together and become very difficult to
disentangle. In the last part we therefore propose and verify a new antenna
design that excites spin waves with only one wave vector. We suggest to use
this antenna design to measure the DMI in thin magnetic layers.Comment: 12 pages, 4 figure
Spin motive forces due to magnetic vortices and domain walls
We study spin motive forces, i.e, spin-dependent forces, and voltages induced
by time-dependent magnetization textures, for moving magnetic vortices and
domain walls. First, we consider the voltage generated by a one-dimensional
field-driven domain wall. Next, we perform detailed calculations on
field-driven vortex domain walls. We find that the results for the voltage as a
function of magnetic field differ between the one-dimensional and vortex domain
wall. For the experimentally relevant case of a vortex domain wall, the
dependence of voltage on field around Walker breakdown depends qualitatively on
the ratio of the so-called -parameter to the Gilbert damping constant,
and thus provides a way to determine this ratio experimentally. We also
consider vortices on a magnetic disk in the presence of an AC magnetic field.
In this case, the phase difference between field and voltage on the edge is
determined by the parameter, providing another experimental method to
determine this quantity.Comment: 8 pages, 9 figures, submitted to PR
Aerobic exercise as a tool to improve hippocampal plasticity and function in humans: practical implications for mental health treatment
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