4,791 research outputs found
Frequency and power dependence of spin-current emission by spin pumping in a thin film YIG/Pt system
This paper presents the frequency dependence of the spin current emission in
a hybrid ferrimagnetic insulator/normal metal system. The system is based on a
ferrimagnetic insulating thin film of Yttrium Iron Garnet (YIG, 200 nm) grown
by liquid-phase-epitaxy (LPE) coupled with a normal metal with a strong
spin-orbit coupling (Pt, 15 nm). The YIG layer presents an isotropic behaviour
of the magnetization in the plane, a small linewidth, and a roughness lower
than 0.4 nm. Here we discuss how the voltage signal from the spin current
detector depends on the frequency [0.6 - 7 GHz], the microwave power, Pin, [1 -
70 mW], and the in-plane static magnetic field. A strong enhancement of the
spin current emission is observed at low frequencies, showing the appearance of
non-linear phenomena.Comment: 7 pages, 5 figure
Volar Perilunate Dislocation: A Case Report and Review of the Literature
Perilunate dislocations, lunate dislocations and perilunate fracture dislocations are rare injuries comprising of less than 10% of all wrist injuries. Volar peri-lunate dislocations (VPLDs) account for less than 3% of perilunate dislocations. These severe carpal injuries occur after high-energy trauma to the wrist and falls on the outstretched hand. We present a case of a missed VPLD who developed parasthesia in the distribution of the median nerve 18 months after the initial injury. A plain film radiograph revealed a stage II VPLD. Nerve conduction studies confirmed compression of the median nerve at the carpal tunnel. VPLDs are extremely rare injuries. A quarter of perilunate dislocations are missed on initial presentation. The outcome is poor for missed injuries and this patient is aware that a wrist fusion may be required in the future for to treat symptoms
Criteria for accurate determination of the magnon relaxation length from the nonlocal spin Seebeck effect
The nonlocal transport of thermally generated magnons not only unveils the
underlying mechanism of the spin Seebeck effect, but also allows for the
extraction of the magnon relaxation length () in a magnetic
material, the average distance over which thermal magnons can propagate. In
this study, we experimentally explore in yttrium iron garnet (YIG)/platinum
systems much further ranges compared with previous investigations. We observe
that the nonlocal SSE signals at long distances () clearly deviate from a
typical exponential decay. Instead, they can be dominated by the nonlocal
generation of magnon accumulation as a result of the temperature gradient
present away from the heater, and decay geometrically as . We emphasize
the importance of looking only into the exponential regime (i.e., the
intermediate distance regime) to extract . With this principle, we
study as a function of temperature in two YIG films which are 2.7
and 50 m in thickness, respectively. We find to be around 15
m at room temperature and it increases to 40 m at 3.5 K. Finite
element modeling results agree with experimental studies qualitatively, showing
also a geometrical decay beyond the exponential regime. Based on both
experimental and modeling results we put forward a general guideline for
extracting from the nonlocal spin Seebeck effect.Comment: 9 pages, 7 figure
Observation of the spin Peltier effect
We report the observation of the spin Peltier effect (SPE) in the
ferrimagnetic insulator Yttrium Iron Garnet (YIG), i.e. a heat current
generated by a spin current flowing through a Platinum (Pt)|YIG interface. The
effect can be explained by the spin torque that transforms the spin current in
the Pt into a magnon current in the YIG. Via magnon-phonon interactions the
magnetic fluctuations modulate the phonon temperature that is detected by a
thermopile close to the interface. By finite-element modelling we verify the
reciprocity between the spin Peltier and spin Seebeck effect. The observed
strong coupling between thermal magnons and phonons in YIG is attractive for
nanoscale cooling techniques.Comment: 5 pages, 3 figures, 4 pages supplementary information, 4
supplementary figure
Magnetic resonance spectroscopy of perpendicularly magnetized permalloy multilayer disks
Using a Magnetic Resonance Force Microscope, we compare the ferromagnetic
resonance spectra of individual micron-size disks with identical diameter, 1
m, but different layer structures. For a disk composed of a single 43.3 nm
thick permalloy (Py) layer, the lowest energy mode in the perpendicular
configuration is the uniform precession. The higher energy modes are standing
spin-waves confined along the diameter of the disk. For a Cu(30)/Py(100)/Cu(30)
nm multilayer structure, it has been interpreted that the lowest energy mode
becomes a precession localized at the Cu/Py interfaces. When the multilayer is
changed to Py(100)/Cu(10)/Py(10) nm, this localized mode of the thick layer is
coupled to the precession of the thin layer
Anesthesie topique par oxybuprocaine dans la chirurgie de cataracte: Ă propos de 100 cas
L'anesthésie topique lors de la chirurgie de la cataracte par phacoemulsification est devenue le meilleur choix pour les ophtalmologistes, Nous rapportons les résultats d'une étude prospective incluant 100 cas de cataractes simples opérées sous anesthésie topique par Oxybuprocaïne 0.4%, l'objectif est d'évaluer les avantages et les inconvénients, l'efficacité et la tolérance de ce protocole dans la chirurgie de cataracte par phacoemulsification. Étude prospective portant sur 100 patients opérés pour cataracte simple stade I, II et III sous anesthésie topique par instillation de quatre gouttes d'Oxybuprocaïne 0.4% collyre, nous avons analysé les complications rencontrées et le confort des patients à l'aide de l'échelle visuelle analogique. La tolérance du patient durant l'acte chirurgical est excellente ainsisur échelle visuelle analogique(EVA) de la douleur était de au alentour de 1 dans la majorité des cas (87 cas/ 92) soit (94% des cas). Ce protocole d'anesthésie topique permet l'éviction de toutes les complications liées aux anesthésies péribulbaire, latérobulbaire ou sous ténonienne et les risques de toxicité endothéliale par injection d'anesthésique intracamérulaire et semble apporter une efficacité anesthésique suffisante, une excellente tolérance. Dans 92% des cas, une anesthésie topique de surface par Oxybuprocaïne 0.4% collyre apparaît suffisante pour une chirurgie de cataracte simple
Bayesian Probabilities and the Histories Algebra
We attempt a justification of a generalisation of the consistent histories
programme using a notion of probability that is valid for all complete sets of
history propositions. This consists of introducing Cox's axioms of probability
theory and showing that our candidate notion of probability obeys them. We also
give a generalisation of Bayes' theorem and comment upon how Bayesianism should
be useful for the quantum gravity/cosmology programmes.Comment: 10 pages, accepted by Int. J. Theo. Phys. Feb 200
Green network protocols and algorithms
Lloret, J.; Ghafoor, KZ.; Rawat, DB.; Nasser, Y. (2015). Green network protocols and algorithms. Journal of Network and Computer Applications. 58:192-193. https://doi.org/10.1016/j.jnca.2015.11.004S1921935
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