Pinning dependent field driven domain wall dynamics and thermal scaling in an ultrathin Pt/Co/Pt magnetic film

Magnetic field-driven domain wall motion in an ultrathin Pt/Co(0.45nm)/Pt ferromagnetic film with perpendicular anisotropy is studied over a wide temperature range. Three different pinning dependent dynamical regimes are clearly identified: the creep, the thermally assisted flux flow and the depinning, as well as their corresponding crossovers. The wall elastic energy and microscopic parameters characterizing the pinning are determined. Both the extracted thermal rounding exponent at the depinning transition, $\psi=$0.15, and the Larkin length crossover exponent, $\phi=$0.24, fit well with the numerical predictions.Comment: 5 pages, 4 figure

Dynamic Formation of Metastable Intermediate State Patterns in Type-I Superconductors

Structure of the intermediate state in type-I superconducting lead (Pb) is shown to be very sensitive to the ramp rate of an applied magnetic field. The configurations of resulting static patterns depend sensitively on the shape of the specimen. In particular, geometric barrier, present in the samples with rectangular cross-section, plays an important role in determining the sharp boundary between the phases of different topology. We propose that seemingly laminar (stripe) pattern obtained as a result of the fast field ramp is simply an imprint left behind by the fast-moving flux tubes. Our results confirm that flux tube phase is topologically favorable.Comment: to be presented at LT-25 (Amsterdam, 2008

Field-Driven Domain-Wall Dynamics in GaMnAs Films with Perpendicular Anisotropy

We combine magneto-optical imaging and a magnetic field pulse technique to study domain wall dynamics in a ferromagnetic (Ga,Mn)As layer with perpendicular easy axis. Contrary to ultrathin metallic layers, the depinning field is found to be smaller than the Walker field, thereby allowing for the observation of the steady and precessional flow regimes. The domain wall width and damping parameters are determined self-consistently. The damping, 30 times larger than the one deduced from ferromagnetic resonance, is shown to essentially originate from the non-conservation of the magnetization modulus. An unpredicted damping resonance and a dissipation regime associated with the existence of horizontal Bloch lines are also revealed

Universal Critical Exponents of the Magnetic Domain Wall Depinning Transition

Magnetic field driven domain wall dynamics in a ferrimagnetic GdFeCo thin film with perpendicular magnetic anisotropy is studied using low temperature magneto-optical Kerr microscopy. Measurements performed in a practically athermal condition allow for the direct experimental determination of the velocity ($\beta = 0.30 \pm 0.03$) and correlation length ($\nu = 1.3 \pm 0.3$) exponents of the depinning transition. The whole family of exponents characterizing the transition is deduced, providing evidence that the depinning of magnetic domain walls is better described by the quenched Edwards-Wilkinson universality class.Comment: 6 pages, 3 figures. Ancillary Material with 10 pages and 4 figures is also include

Reverse wedge osteotomy of the distal radius in Madelung's deformity

Madelung\u27s deformity results from a growth defect in the palmar and ulnar region of the distal radius. It presents as an excessively inclined radial joint surface, inducing "spontaneous progressive palmar subluxation of the wrist". The principle of reverse wedge osteotomy (RWO) consists in the reorientation of the radial joint surface by taking a circumferential bone wedge, the base of which is harvested from the excess of the radial and dorsal cortical bone of the distal radius, then turning it over and putting back this reverse wedge into the osteotomy so as to obtain closure on the excess and opening on the deficient cortical bone. RWO corrects the palmar subluxation of the carpus and improves distal radio-ulnar alignment. All five bilaterally operated patients were satisfied, esthetically and functionally. Its corrective power gives RWO a place apart among the surgical techniques currently available in Madelung\u27s deformity

Association of soluble markers of inflammation with peri-coronary artery inflammation in people with and without HIV infection and without cardiovascular disease

BACKGROUND: Inflammation is linked to elevated cardiovascular disease (CVD) risk in people with HIV (PWH) on antiretroviral therapy (ART). Fat attenuation index (FAI) is a measure of peri-coronary inflammation that independently predicts CVD risk in HIV-uninfected persons. Whether FAI is associated with soluble inflammatory markers is unknown. METHODS: Plasma levels of inflammatory markers were measured in 58 PWH and 16 controls without current symptoms or prior known CVD who underwent coronary computed tomography angiography and had FAI measurements. A cross-sectional analysis was performed, and associations of markers with FAI values of the right coronary artery (RCA) and left anterior descending artery (LAD) were assessed using multivariable regression models adjusted for the potential confounders age, sex, race, low-density lipoprotein cholesterol, body mass index, and use of lipid-lowering medication. RESULTS: Several inflammatory markers had significant associations with RCA or LAD FAI in adjusted models, including sCD14, sCD163, TNFR-I, and TNFR-II, CCL5, CX3CL1, IP-10. CONCLUSIONS: The associations between indices of systemic and peri-coronary inflammation are novel and suggest that these systemic markers and FAI together are promising noninvasive biomarkers that can be applied to assess asymptomatic CVD in people with and without HIV; they also may be useful tools to evaluate effects of anti-inflammatory interventions

Wire edge dependent magnetic domain wall creep

open13While edge pinning is known to play an important role in sub-μm wires, we demonstrate that strong deviations from the universal creep law can occur in 1 to 20 μm wide wires. Magnetic imaging shows that edge pinning translates into a marked bending of domain walls at low drive and is found to depend on the wire fabrication process and aging. Edge pinning introduces a reduction of domain wall velocity with respect to full films which increasingly dominates the creep dynamics as the wire width decreases. We show that the deviations from the creep law can be described by a simple model including a counter magnetic field which links the width of the wire to the edge dependent pinning strength. This counter field defines a key nonuniversal contribution to creep motion in patterned structures.openHerrera Diez, L.; Jeudy, V.; Durin, G.; Casiraghi, A.; Liu, Y. T.; Voto, M.; Agnus, G.; Bouville, D.; Vila, L.; Langer, J.; Ocker, B.; Lopez-Diaz, L.; Ravelosona, D.Herrera Diez, L.; Jeudy, V.; Durin, G.; Casiraghi, A.; Liu, Y. T.; Voto, M.; Agnus, G.; Bouville, D.; Vila, L.; Langer, J.; Ocker, B.; Lopez-Diaz, L.; Ravelosona, D

Magnetic domain wall curvature induced by wire edge pinning

open14In this study, we report on the analysis of the magnetic domain wall (DW) curvature due to magnetic field induced motion in Ta/CoFeB/MgO and Pt/Co/Pt wires with perpendicular magnetic anisotropy. In wires of 20 mu m and 25 mu m, a large edge pinning potential produces the anchoring of the DW ends to the wire edges, which is evidenced as a significant curvature of the DW front as it propagates. As the driving magnetic field is increased, the curvature reduces as a result of the system moving away from the creep regime of DW motion, which implies a weaker dependence of the DW dynamics on the interaction between the DW and the wire edge defects. A simple model is derived to describe the dependence of the DW curvature on the driving magnetic field and allows us to extract the parameter sigma (E), which accounts for the strength of the edge pinning potential. The model describes well the systems with both weak and strong bulk pinning potentials like Ta/CoFeB/MgO and Pt/Co/Pt, respectively. This provides a means to quantify the effect of edge pinning induced DW curvature on magnetic DW dynamics.embargoed_20210815Herrera Diez, L.; Ummelen, F.; Jeudy, V.; Durin, G.; Lopez-Diaz, L.; Diaz-Pardo, R.; Casiraghi, A.; Agnus, G.; Bouville, D.; Langer, J.; Ocker, B.; Lavrijsen, R.; Swagten, H. J. M.; Ravelosona, D.Herrera Diez, L.; Ummelen, F.; Jeudy, V.; Durin, G.; Lopez-Diaz, L.; Diaz-Pardo, R.; Casiraghi, A.; Agnus, G.; Bouville, D.; Langer, J.; Ocker, B.; Lavrijsen, R.; Swagten, H. J. M.; Ravelosona, D

An automatic critical care urine meter

Nowadays patients admitted to critical care units have most of their physiological parameters measured automatically by sophisticated commercial monitoring devices. More often than not, these devices supervise whether the values of the parameters they measure lie within a pre-established range, and issue warning of deviations from this range by triggering alarms. The automation of measuring and supervising tasks not only discharges the healthcare staff of a considerable workload but also avoids human errors in these repetitive and monotonous tasks. Arguably, the most relevant physiological parameter that is still measured and supervised manually by critical care unit staff is urine output (UO). In this paper we present a patent-pending device that provides continuous and accurate measurements of patient’s UO. The device uses capacitive sensors to take continuous measurements of the height of the column of liquid accumulated in two chambers that make up a plastic container. The first chamber, where the urine inputs, has a small volume. Once it has been filled it overflows into a second bigger chamber. The first chamber provides accurate UO measures of patients whose UO has to be closely supervised, while the second one avoids the need for frequent interventions by the nursing staff to empty the containe