42 research outputs found
Large voltage-induced modification of spin-orbit torques in Pt/Co/GdOx
We report on large modifications of current-induced spin-orbit torques in a
gated Pt/Co/Gd-oxide microstrip due to voltage-driven O migration. The
Slonczewski-like and field-like torques are quantified using a low-frequency
harmonic technique based on the polar magneto-optical Kerr effect.
Voltage-induced oxidation of Co enhances the Slonczewski-like torque by as much
as an order of magnitude, and simultaneously reduces the anisotropy energy
barrier by a factor of ~5. Such magneto-ionic tuning of interfacial spin-orbit
effects may significantly enhance the efficiency of magnetization switching and
provide additional degrees of freedom in spintronic devices
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Light-guiding hydrogels for cell-based sensing and optogenetic synthesis in vivo
Polymer hydrogels are widely used as cell scaffolds for biomedical applications. While the biochemical and biophysical properties of hydrogels have been extensively investigated, little attention has been paid to their potential photonic functionalities. Here, we report cell-integrated polyethylene glycol-based hydrogels for in-vivo optical sensing and therapy applications. Hydrogel patches containing cells were implanted in awake, freely moving mice for several days and shown to offer long-term transparency, biocompatibility, cell-viability, and light-guiding properties (loss: <1 dB/cm). Using optogenetic, glucagon-like peptide-1 (GLP-1) secreting cells, we conducted light-controlled therapy using the hydrogel in a mouse model with type-2 diabetes and attained improved glucose homeostasis. Furthermore, real-time optical readout of encapsulated heat-shock-protein-coupled fluorescent reporter cells made it possible to measure the nanotoxicity of cadmium-based bare and shelled quantum dots (CdTe; CdSe/ZnS) in vivo
Deterministic creation and deletion of a single magnetic skyrmion observed by direct time-resolved X-ray microscopy
Spintronic devices based on magnetic skyrmions are a promising candidate for
next-generation memory applications due to their nanometre-size,
topologically-protected stability and efficient current-driven dynamics. Since
the recent discovery of room-temperature magnetic skyrmions, there have been
reports of current-driven skyrmion displacement on magnetic tracks and
demonstrations of current pulse-driven skyrmion generation. However, the
controlled annihilation of a single skyrmion at room temperature has remained
elusive. Here we demonstrate the deterministic writing and deleting of single
isolated skyrmions at room temperature in ferrimagnetic GdFeCo films with a
device-compatible stripline geometry. The process is driven by the application
of current pulses, which induce spin-orbit torques, and is directly observed
using a time resolved nanoscale X-ray imaging technique. We provide a
current-pulse profile for the efficient and deterministic writing and deleting
process. Using micromagnetic simulations, we also reveal the microscopic
mechanism of the topological fluctuations that occur during this process.Comment: 27 pages, 4 figure
Statement on chronotherapy for the treatment of hypertension: consensus document from the Korean society of hypertension
Nocturnal blood pressure (BP) has been shown to have a significant predictive value for cardiovascular disease. In some cases, it has a superior predictive value for future cardiovascular outcomes than daytime BP. As efficacy of BP medications wanes during nighttime and early morning, control of nocturnal hypertension and morning hypertension can be difficult. As such, chronotherapy, the dosing of BP medication in the evening, has been an ongoing topic of interest in the field of hypertension. Some studies have shown that chronotherapy is effective in reducing nocturnal BP, improving non dipping and rising patterns to dipping patterns, and improving cardiovascular prognosis. However, criticism and concerns have been raised regarding the design of these studies, such as the Hygia study, and the implausible clinical benefits in cardiovascular outcomes considering the degree of BP lowering from bedtime dosing. Studies have shown that there is no consistent evidence to suggest that routine administration of antihypertensive medications at bedtime can improve nocturnal BP and early morning BP control. However, in some cases of uncontrolled nocturnal hypertension and morning hypertension, such as in those with diabetes mellitus, chronic kidney disease, and obstructive sleep apnea, bedtime dosing has shown efficacy in reducing evening and early morning BP. The recently published the Treatment in Morning versus Evening (TIME) study failed to demonstrate benefit of bedtime dosing in reducing cardiovascular outcomes in patients with hypertension. With issues of the Hygia study and negative results from the TIME study, it is unclear at this time whether routine bedtime dosing is beneficial for reducing cardiovascular outcomes