Search

Epitaxial metal/oxide based magnetic tunnel-junctions (MTJ) are valuable model systems to investigate the influence of the crystallinity of individual layers on the magnetic properties. We have non-destructively studied the effect of the optical lithography procedure on the crystalline structure of MTJ's with lateral spatial resolution by performing local x-ray diffraction experiments using a microfocused x-ray spot. We demonstrate that the lithography process produces distortion effects on the crystalline structure of the layers near the edges of the lithographed junction. These distortions are present on all the constituent layers and are most probably driven by the elastic constants of the materials. They translate into tilts of the crystalline planes in the vicinity of the edges and propagate towards the center of the junction; the tilt's amplitude (up to several degrees) and sign (concave or convex) depend on the junction's shape, size and the type of materials (interfaces) used. We report results for junctions made with two types of metal-oxide interfaces (Co/CoFe2O4and Co/Fe3O4), with sizes from 10 to 150 μm and various shapes (square-, rectangle- and disk-like).

In standard diffraction experiments, ensembles of objects are characterized yielding averaged, statistical properties (meaningful only if the ensemble is monodisperse). Focused x-ray beams are used here to localize single nanostructures, identifying and probing individual objects one by one. In a scanning mode, a 2-dimensional image of the sample is recorded, which allows the reproducible alignment of a specific nanostructure for analysis. The x-ray scattered signal is analyzed and modelled, to give access to the shape, strain and composition inside the single object with sub-micron resolution. Combination of x-ray microdiffraction technique with other micro-probe experiments on the very same individual object (simultaneous coupling of x-ray diffraction measurements with atomic force microscopy (AFM)) is also shown; we prove the possibility to interact with the objects and to address elastic properties for individual nano-structures out of an ensemble.

We present a study of the atomic surface diffusion at low temperature of Cr adatoms deposited on Cu(100), Cu(111), and Au(111) surfaces. Time-dependent X-ray magnetic circular dichroism (XMCD), Monte Carlo simulations, and the Kimball−Shortley iterative method are used to evidence a mechanism of quantum tunneling involved in the Cr adatom surface diffusion at temperatures below 40 K. We show that the XMCD line shape is correlated to the atomic configuration of Cr deposited on a metallic surface. A diffusion rate ranging from 0.03 Hz for Cu(100) to 30 Hz for Au(111) at 10 K is reported from the time evolution of the XMCD line shape. A quantum equation of motion for the Cr adatom is derived and solved by using a Kimball−Shortley iterative method. Good agreement between the calculated Bohr periods and the experimental diffusion rates is reported.

Abstract: Epitaxial metal/oxide based magnetic tunnel-junctions (MTJ) are valuable model systems to investigate the influence of the crystallinity of individual layers on the magnetic properties. We have non-destructively studied the effect of the optical lithography procedure on the crystalline structure of MTJ’s with lateral spatial resolution by performing local x-ray diffraction experiments using a microfocused x-ray spot. We demonstrate that the lithography process produces distortion effects on the crystalline structure of the layers near the edges of the lithographed junction. These distortions are present on all the constituent layers and are most probably driven by the elastic constants of the materials. They translate into tilts of the crystalline planes in the vicinity of the edges and propagate towards the center of the junction; the tilt’s amplitude (up to several degrees) and sign (concave or convex) depend on the junction’s shape, size and the type of materials (interfaces) used. We report results for junctions made with two types of metal-oxide interfaces (Co/CoFe2O4 and Co/Fe3O4), with sizes from 10 to 150 μm and various shapes (square-, rectangle- and disk-like).

Epitaxial metal/oxide based magnetic tunnel-junctions (MTJ) are valuable model systems to investigate the influence of the crystallinity of individual layers on the magnetic properties. We have non-destructively studied the effect of the optical lithography procedure on the crystalline structure of MTJ's with lateral spatial resolution by performing local x-ray diffraction experiments using a microfocused x-ray spot. We demonstrate that the lithography process produces distortion effects on the crystalline structure of the layers near the edges of the lithographed junction. These distortions are present on all the constituent layers and are most probably driven by the elastic constants of the materials. They translate into tilts of the crystalline planes in the vicinity of the edges and propagate towards the center of the junction; the tilt's amplitude (up to several degrees) and sign (concave or convex) depend on the junction's shape, size and the type of materials (interfaces) used. We report results for junctions made with two types of metal-oxide interfaces (Co/CoFe2O4and Co/Fe3O4), with sizes from 10 to 150??m and various shapes (square-, rectangle- and disk-like).

(Anaesthesia. 2020;75:89–95)Effective pain management after cesarean delivery is crucial both for maternal satisfaction with their delivery experience and their ability to devote their care and attention to their newborns. Neuraxial opioids have been a mainstay of postcesarean pain management, but there are significant drawbacks with these medications, including the potential for misuse. Another analgesic option for postcesarean analgesia is the quadratus lumborum block (QLB). The literature has indicated that QLB is safe and easy to perform after cesarean delivery and has shown superiority over transversus abdominis plane block. Yet, adding QLB to a standard multimodal analgesic regimen that includes intrathecal morphine has not yet been evaluated. The aim of this study was to assess the efficacy of QLB when added to a standard protocol that includes intrathecal morphine for the management of postcesarean pain after cesarean delivery.

Abstract: Neutron activation analysis combined with chemical preconcentration of the elements in water samples can give a high sensitivity in the determination of concentrations for In-EDTA, I– and Br– used as activable tracers in hydrological studies. The authors have developed an improved method of analysis which is sensitive, selective and applicable to a wide range of underground and surface water samples including those having a high concentration of manganese ions.

For Abstract see ChemInform Abstract in Full Text.