50 research outputs found
Venous thromboembolism in Multiple myeloma – choice of prophylaxis, role of direct oral anticoagulants and special considerations
High Rates of Prolonged Molecular Remissions After Tandem Autologous-Nonmyeloablative Allografting in Newly Diagnosed Myeloma
High Rates of Prolonged Molecular Remissions After Tandem Autologous-Nonmyeloablative Allografting in Newly Diagnosed Myeloma
Predictive Factors and Risk Model for Positive Circumferential Resection Margin Rate after Transanal Total Mesorectal Excision in 2653 Patients with Rectal Cancer
Resistive switching in manganite/graphene hybrid planar nanostructures
We report on the fabrication and magnetotransport characterization of hybrid graphene-based nanodevices with epitaxial nanopatterned La_(0.7)Sr_(0.3)MnO_(3) manganite electrodes grown on SrTiO_(3)(100). The few-layer graphene was deposited onto the predefined manganite nanowires by using a mechanical transfer technique. These nanodevices exhibit resistive switching and hysteretic transport as measured by current-voltage curves. The resistance can be reversibly switched between high and low states, yielding a consistent non-volatile memory response. The effect is discussed in terms of changes in the concentration of oxygen vacancies at the space charge region of the Schottky barriers building at the contacts
Paving the way to nanoionics: atomic origin of barriers for ionic transport through interfaces
The blocking of ion transport at interfaces strongly limits the performance of electrochemical nanodevices for energy applications. The barrier is believed to arise from space-charge regions generated by mobile ions by analogy to semiconductor junctions. Here we show that something different is at play by studying ion transport in a bicrystal of yttria (9% mol) stabilized zirconia (YSZ), an emblematic oxide ion conductor. Aberration-corrected scanning transmission electron microscopy (STEM) provides structure and composition at atomic resolution, with the sensitivity to directly reveal the oxygen ion profile. We find that Y segregates to the grain boundary at Zr sites, together with a depletion of oxygen that is confined to a small length scale of around 0.5nm. Contrary to the main thesis of the space-charge model, there exists no evidence of a long-range O vacancy depletion layer. Combining ion transport measurements across a single grain boundary by nanoscale electrochemical strain microscopy (ESM), broadband dielectric spectroscopy measurements, and density functional calculations, we show that grain-boundary-induced electronic states act as acceptors, resulting in a negatively charged core. Besides the possible effect of the modified chemical bonding, this negative charge gives rise to an additional barrier for ion transport at the grain boundary