Driving skyrmions in a composite bilayer

Abstract

Magnetic skyrmions and multiferroics are the most interesting objects in nanostructure science that have great potential in future spin-electronic technology. The study of the multiferroic skyrmions has attracted much interest in recent years. This paper reports on the magnetic skyrmions induced by an electric driving field on a composite multiferroic lattice. By using the spin dynamics method, we use a classical magnetic spin model and an electric pseudospin model, which are coupled by a strong magnetoelectric coupling in the dynamical simulations. Interestingly, we observe some skyrmion-like objects on the electric component during the switching process, which is due to the connection between the electric and the magnetic structures.

An achiral ferromagnetic/chiral antiferromagnetic bilayer system leading to controllable size and density of skyrmions

“…Magnetic skyrmions exist in non-centrosymmetric bulk ferromagnets and magnetic thin films with a lack or breakdown of inversion symmetry 1 . Since their first experimental observation in 2009 2 , magnetic skyrmions have been found in bulk materials, including ferromagnets 2–7 , multiferroics 8 , and antiferromagnets 9–13 , as well as in ultrathin films 14 and multilayers 15,16 . Magnetic skyrmions are widely investigated to understand their unique properties including the size, stability and the extremely low depinning current needed to move them 17–20 , namely 10 6 A/m 2 as compared to 10 12 A/m 2 for domain walls 1 .…”

“…However, it needs to be emphasized that most of these materials have a low Curie temperature and low anisotropy due to weak FM interactions. Researchers even turned to some materials without DMI, where skyrmions or biskyrmions were stabilized well beyond room temperature by magnetostatic interaction 15,33 , albeit their geometry dependence is not easy to control.…”

The spin structures of interlayer coupled magnetic films with opposite chirality

“…It is also highly mobile with small spin currents since its current induced translational motion does not accompany the dissipation of energy 10 , 11 . Extensive researches have been focused on manipulating the properties and dynamics of skyrmions 12 – 14 .…”

Secure key distribution over a 500 km long link using a Raman ultra‐long fiber laser

“…In addition to security, practical considerations such as the link propagation loss and dark‐counts in single‐photon detectors pose substantial limitations on the link range and the bit‐rate achievable by QKD systems. Although the introduction of decoy states and avalanche InGaAs photo‐detectors can facilitate GHz clock rate experiments and ranges of 250 km using special ultra‐low loss fibers, a simple classical key‐distribution scheme employing conventional, off‐the‐shelf, components and facilitating long link ranges and high bit‐rates,still remains highly attractive.…”