Vortex-assisted domain wall depinning and propagation in notched nanowires

Various notches are often introduced in spintronics to trap a domain wall (DW). Common wisdom would expect notches to strengthen DW pinning and to hinder DW motion. Interestingly, our simulations show that notches help electric current to depin a DW with the assistance of vortex generation. The DW displacement is insensitive to notch geometry and current density. This phenomenon is explained by the Thiele equation. Moreover, a current density below the intrinsic threshold value, which is the minimum current to sustain continuous DW motion in a uniform nanowire, can induce a continuous DW propagation along a wire with a series of notches

Influence of Distal Residue B10 on CO Dynamics in Myoglobin and Neuroglobin

For many years, myoglobin has served as a paradigm for structure–function studies in proteins. Ligand binding and migration within myoglobin has been studied in great detail by crystallography and spectroscopy, showing that gaseous ligands such as O2, CO, and NO not only bind to the heme iron but may also reside transiently in three internal ligand docking sites, the primary docking site B and secondary sites C and D. These sites affect ligand association and dissociation in specific ways. Neuroglobin is another vertebrate heme protein that also binds small ligands. Ligand migration pathways in neuroglobin have not yet been elucidated. Here, we have used Fourier transform infrared temperature derivative spectroscopy at cryogenic temperatures to compare the influence of the side chain volume of amino acid residue B10 on ligand migration to and rebinding from docking sites in myoglobin and neuroglobin