5 results
Search Results
Now showing 1 - 5 of 5
- ItemImaging of buried 3D magnetic rolled-up nanomembranes(Washington, DC : American Chemical Society, 2014) Streubel, R.; Han, L.; Kronast, F.; Ünal, A.A.; Schmidt, O.G.; Makarov, D.Increasing performance and enabling novel functionalities of microelectronic devices, such as three-dimensional (3D) on-chip architectures in optics, electronics, and magnetics, calls for new approaches in both fabrication and characterization. Up to now, 3D magnetic architectures had mainly been studied by integral means without providing insight into local magnetic microstructures that determine the device performance. We prove a concept that allows for imaging magnetic domain patterns in buried 3D objects, for example, magnetic tubular architectures with multiple windings. The approach is based on utilizing the shadow contrast in transmission X-ray magnetic circular dichroism (XMCD) photoemission electron microscopy and correlating the observed 2D projection of the 3D magnetic domains with simulated XMCD patterns. That way, we are not only able to assess magnetic states but also monitor the field-driven evolution of the magnetic domain patterns in individual windings of buried magnetic rolled-up nanomembranes.
- ItemA highly flexible and compact magnetoresistive analytic device(London [u.a.] : Royal Society of Chemistry, 2014) Lin, G.; Makarov, D.; Melzer, M.; Si, W.; Yan, C.; Schmidt, O.G.A grand vision of realization of smart and compact multifunctional microfluidic devices for wearable health monitoring, environment sensing and point-of-care tests emerged with the fast development of flexible electronics. As a vital component towards this vision, magnetic functionality in flexible fluidics is still missing although demanded by the broad utility of magnetic nanoparticles in medicine and biology. Here, we demonstrate the first flexible microfluidic analytic device with integrated high-performance giant magnetoresistive (GMR) sensors. This device can be bent to a radius of 2 mm while still retaining its full performance. Various dimensions of magnetic emulsion droplets can be probed with high precision using a limit of detection of 0.5 pl, providing broad applicability in high-throughput droplet screening, flow cytometry and drug development. The flexible feature of this analytic device holds great promise in the realization of wearable, implantable multifunctional platforms for biomedical, pharmaceutical and chemical applications.
- ItemMagnetosensitive e-skins with directional perception for augmented reality(Washington : American Association for the Advancement of Science (A A A S), 2018) Cañón Bermúdez, G.S.; Karnaushenko, D.D.; Karnaushenko, D.; Lebanov, A.; Bischoff, L.; Kaltenbrunner, M.; Fassbender, J.; Schmidt, O.G.; Makarov, D.Electronic skins equipped with artificial receptors are able to extend our perception beyond the modalities that have naturally evolved. These synthetic receptors offer complimentary information on our surroundings and endow us with novel means of manipulating physical or even virtual objects. We realize highly compliant magnetosensitive skins with directional perception that enable magnetic cognition, body position tracking, and touchless object manipulation. Transfer printing of eight high-performance spin valve sensors arranged into two Wheatstone bridges onto 1.7-mm-thick polyimide foils ensures mechanical imperceptibility. This resembles a new class of interactive devices extracting information from the surroundings through magnetic tags. We demonstrate this concept in augmented reality systems with virtual knob-turning functions and the operation of virtual dialing pads, based on the interaction with magnetic fields. This technology will enable a cornucopia of applications from navigation, motion tracking in robotics, regenerative medicine, and sports and gaming to interaction in supplemented reality.
- ItemMesoscale Dzyaloshinskii-Moriya interaction: Geometrical tailoring of the magnetochirality(London : Nature Publishing Group, 2018) Volkov, O.M.; Sheka, D.D.; Gaididei, Y.; Kravchuk, V.P.; Rößler, U.K.; Fassbender, J.; Makarov, D.Crystals with broken inversion symmetry can host fundamentally appealing and technologically relevant periodical or localized chiral magnetic textures. The type of the texture as well as its magnetochiral properties are determined by the intrinsic Dzyaloshinskii-Moriya interaction (DMI), which is a material property and can hardly be changed. Here we put forth a method to create new artificial chiral nanoscale objects with tunable magnetochiral properties from standard magnetic materials by using geometrical manipulations. We introduce a mesoscale Dzyaloshinskii-Moriya interaction that combines the intrinsic spin-orbit and extrinsic curvature-driven DMI terms and depends both on the material and geometrical parameters. The vector of the mesoscale DMI determines magnetochiral properties of any curved magnetic system with broken inversion symmetry. The strength and orientation of this vector can be changed by properly choosing the geometry. For a specific example of nanosized magnetic helix, the same material system with different geometrical parameters can acquire one of three zero-temperature magnetic phases, namely, phase with a quasitangential magnetization state, phase with a periodical state and one intermediate phase with a periodical domain wall state. Our approach paves the way towards the realization of a new class of nanoscale spintronic and spinorbitronic devices with the geometrically tunable magnetochirality.
- ItemMagnetoresistive emulsion analyzer(London : Nature Publishing Group, 2013) Lin, G.; Baraban, L.; Han, L.; Karnaushenko, D.; Makarov, D.; Cuniberti, G.; Schmidt, O.G.We realize a magnetoresistive emulsion analyzer capable of detection, multiparametric analysis and sorting of ferrofluid-containing nanoliter-droplets. The operation of the device in a cytometric mode provides high throughput and quantitative information about the dimensions and magnetic content of the emulsion. Our method offers important complementarity to conventional optical approaches involving ferrofluids, and paves the way to the development of novel compact tools for diagnostics and nanomedicine including drug design and screening.