6,437 research outputs found
Penetration depth study of LaOsSb: Multiband s-wave superconductivity
We measured the magnetic penetration depth in single crystals of
LaOsSb (=0.74 K) down to 85 mK using a tunnel diode
oscillator technique. The observed low-temperature exponential dependence
indicates a s-wave gap. Fitting the low temperature data to BCS s-wave
expression gives the zero temperature gap value which is significantly smaller than the BCS value of 1.76. In
addition, the normalized superfluid density shows an unusually long
suppression near , and are best fit by a two-band s-wave model.Comment: 5 pages, 2 figure
Probing the superconducting gap symmetry of PrRuSb: A comparison with PrOsSb
We report measurements of the magnetic penetration depth in single
crystals of PrRuSb down to 0.1 K. Both and superfluid
density exhibit an exponential behavior for 0.5, with
parameters (0)/\textit{k}\textit{T} = 1.9 and
= 2900 \AA. The value of (0) is consistent with the specific-heat jump
value of = 1.87 measured elsewhere, while the value of
is consistent with the measured value of the electronic
heat-capacity coefficient . Our data are consistent with
PrRuSb being a moderate-coupling, fully-gapped superconductor. We
suggest experiments to study how the nature of the superconducting state
evolves with increasing Ru substitution for Os
Evolution of superconducting order in Pr(OsRu)Sb
We report measurements of the magnetic penetration depth in single
crystals of Pr(OsRu)Sb down to 0.1 K. Both
and superfluid density exhibit an exponential behavior for the
0.4 samples, going from weak (=0.4,0.6), to moderate, coupling
(=0.8). For the 0.2 samples, both and vary as
at low temperatures, but is s-wave-like at intermediate to
high temperatures. Our data are consistent with a three-phase scenario, where a
fully-gapped phase at undergoes two transitions: first to an
unconventional phase at , then to a nodal low-
phase at , for small values of .Comment: Changed title, enlarged numbering in figures 5 pages, 4 figures, 1
tabl
Observation of the spontaneous vortex phase in the weakly ferromagnetic superconductor ErNiBC: A penetration depth study
The coexistence of weak ferromagnetism and superconductivity in ErNiBC suggests the possibility of a spontaneous vortex phase (SVP) in which
vortices appear in the absence of an external field. We report evidence for the
long-sought SVP from the in-plane magnetic penetration depth of high-quality single crystals of ErNiBC. In addition to
expected features at the N\'{e}el temperature = 6.0 K and weak
ferromagnetic onset at K, rises to a maximum
at K before dropping sharply down to 0.1 K. We assign the
0.45 K-maximum to the proliferation and freezing of spontaneous vortices. A
model proposed by Koshelev and Vinokur explains the increasing as a consequence of increasing vortex density, and its subsequent decrease
below as defect pinning suppresses vortex hopping.Comment: 5 pages including figures; added inset to Figure 2; significant
revisions to tex
Novel Activity Detection Algorithm to Characterize Spontaneous Stepping During Multimodal Spinal Neuromodulation After Mid-Thoracic Spinal Cord Injury in Rats.
A mid-thoracic spinal cord injury (SCI) severely impairs activation of the lower limb sensorimotor spinal networks, leading to paralysis. Various neuromodulatory techniques including electrical and pharmacological activation of the spinal networks have been successful in restoring locomotor function after SCI. We hypothesized that the combination of self-training in a natural environment with epidural stimulation (ES), quipazine (Quip), and strychnine (Strych) would result in greater activity in a cage environment after paralysis compared to either intervention alone. To assess this, we developed a method measuring and characterizing the chronic EMG recordings from tibialis anterior (TA) and soleus (Sol) muscles while rats were freely moving in their home cages. We then assessed the relationship between the change in recorded activity over time and motor-evoked potentials (MEPs) in animals receiving treatments. We found that the combination of ES, Quip, and Strych (sqES) generated the greatest level of recovery followed by ES + Quip (qES) while ES + Strych (sES) and ES alone showed least improvement in recorded activity. Further, we observed an exponential relationship between late response (LR) component of the MEPs and spontaneously generated step-like activity. Our data demonstrate the feasibility and potential importance of quantitatively monitoring mechanistic factors linked to activity-dependence in response to combinatorial interventions compared to individual therapies after SCI
Theoretical review on sin2beta(phi_1) from b to s penguins
Recent theoretical results of the standard model expectations on
from penguin-dominated decays are briefly
reviewed.Comment: 6 pages, 3 figures, Flavor Physics & CP Violation Conference, Taipei,
200
Senior Citizens’ Self-Efficacy for ICT Use: The Influence of Gender, Social Influence and Social Support
As the world becomes more digitally connected and most countries have longer life expectancy and an ageing population, it is critical to understand the factors affecting ICT adoption among the senior citizens. Previous researchers examined how various factors influence ICT adoption among senior citizens, including age, degree of functional impairment, financial resources, education level etc. In addition to the demographic factors, psychological factors such as computer self-efficacy (CSE) is also crucial in understanding ICT adoption among seniors. Building upon the classic psychological theory of self-efficacy, we proposed that CSE is an important mediating factor between social influence, social support and usage. We further posit that gender moderates the effect on social support and CSE among senior citizens. Specifically, the effects on women are augmented. To test the developed hypotheses, we conducted a person-administered survey comprising 503 Singaporeans aged between 55 and 75 years of age. Collected data were analysed using partial least squares. The results confirmed the proposed hypotheses and demonstrated that gender, social influence, social support and CSE are crucial in understanding ICT usage amongst seniors. Specific insights on the use of ICT among senior citizens are revealed
Tunable magnetic interaction at the atomic scale in oxide heterostructures
We report on a systematic study of a number of structurally identical but
chemically distinct transition metal oxides in order to determine how the
material-specific properties such as the composition and the strain affect the
properties at the interface of heterostructures. Our study considers a series
of structures containing two layers of ferromagnetic SrRuO3, with
antiferromagnetic insulating manganites sandwiched in between. The results
demonstrate how to control the strength and relative orientation of interfacial
ferromagnetism in correlated electron materials by means of valence state
variation and substrate-induced strain, respectively
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