Spin waves have been studied experimentally and by simulations in 1000 nm side equilateral triangular Permalloy dots in the Buckle state (B, with in-plane field along the triangle base) and the Y state (Y, with in-plane field perpendicular to the bas
e). The excess of exchange energy at the triangles edges creates channels that allow effective spin wave propagation along the edges inthe B state. These quasi one-dimensional spin waves emitted by the vertex magnetic charges gradually transform from propagating to standing due to interference and(as pointed out by simulations) areweakly affected by smallvariations of the aspect ratio(from equilateral to isosceles dots) or by interdot dipolar interaction present in our dot arrays. Spin waves excited in the Y state have mainly a two-dimensional character.Propagation of the spin waves along the edge states in triangular dots opens possibilities for creation of new and versatile spintronic devices.
Broadband magnetization response of equilateral triangular 1000 nm Permalloy dots has been studied under an in-plane magnetic field, applied parallel (buckle state) and perpendicular (Y state) to the triangles base. Micromagnetic simulations identify
edge spin waves (E-SWs) in the buckle state as SWs propagating along the two adjacent edges. These quasi one-dimensional spin waves emitted by the vertex magnetic charges gradually transform from propagating to standing due to interference and are weakly affected by dipolar interdot interaction and variation of the aspect ratio. Spin waves in the Y state have a two dimensional character. These findings open perspectives for implementation of the E-SWs in magnonic crystals and thin films.
Strong pinning of superconducting flux quanta by a square array of 1 $mu$m-sized ferromagnetic dots in a magnetic-vortex state was visualized by low-temperature magnetic force microscopy (LT-MFM). A direct correlation of the superconducting flux line
s with the positions of the dots was derived. The force that the MFM tip exerts on the individual vortex in the depinning process was used to estimate the spatial modulation of the pinning potential. It was found, that the superconducting vortices which are preferably located on top of the Py dots experience about 15 times stronger pinning forces as compared to the pinning force in the pure Nb film. The strong pinning exceeds the repulsive interaction between the superconducting vortices and allows the vortex clusters to be located at each dot. Our microscopic studies are consistent with global magnetoresistace measurements on these hybrid structures.
A new approach based on the domain wall displacement in confined ferromagnetic nanostructures for attracting and sensing a single nanometric magnetic particles is presented. We modeled and experimentally demonstrated the viability of the approach usi
ng an anisotropic magnetoresistance device made by a micron-size square ring of Permalloy designed for application in magnetic storage. This detection concept can be suitable to biomolecular recognition, and in particular to single molecule detection.
