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Effects of magnetic asymmetry on strongly coupled spin-vortex pairs with parallel core polarization and antiparallel chirality in synthetic nanomagnets are investigated. This includes vortex-core length asymmetry, biasing field asymmetry, and pinning of one of the two vortex cores. Our experimental observations as well as analytical and micromagnetic modeling show how magnetic asymmetry can be used to differentiate magneto-resistively otherwise degenerate multiple stable states of a vortex pair. These results expand the knowledge base for spin vortex arrays in nanostructures and should be useful in light of the recent proposals on coding information into multiple topological spin states, such as single and multiple vortex core/chirality states.
Spin vortices in magnetic nanopillars are used as GHz oscillators, with frequency however essentially fixed in fabrication. We demonstrate a model system of a two-vortex nanopillar, in which the resonance frequency can be changed by an order of magni
We report on spin-vortex pair dynamics measured at temperatures low enough to suppress stochastic core motion, thereby uncovering the highly non-linear intrinsic dynamics of the system. Our analysis shows that the decoupling of the two vortex cores i
We investigate magnetic nano-pillars, in which two thin ferromagnetic nanoparticles are separated by a nanometer thin nonmagnetic spacer and can be set into stable spin vortex-pair configurations. The 16 ground states of the vortex-pair system are ch
Vortex pairs in magnetic nanopillars with strongly coupled cores and pinning of one of the cores by a morphological defect, are used to perform resonant pinning spectroscopy, in which a microwave excitation applied to the nanopillar produces pinning
We study the spin-resolved transport through single-level quantum dots strongly coupled to ferromagnetic leads in the Kondo regime, with a focus on contact and material asymmetry-related effects. By using the numerical renormalization group method, w