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Version: publishedVersion × Publisher: Hoboken, NJ : Wiley × WGL Institute: IFWD ×

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Now showing 1 - 10 of 24
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    Self‐assembled on‐chip‐integrated giant magneto‐impedance sensorics
    (Hoboken, NJ : Wiley, 2015) Karnaushenko, Daniil; Karnaushenko, Dmitriy D.; Makarov, Denys; Baunack, Stefan; Schäfer, Rudolf; Schmidt, Oliver G.
    A novel method relying on strain engineering to realize arrays of on‐chip‐integrated giant magneto‐impedance (GMI) sensors equipped with pick‐up coils is put forth. The geometrical transformation of an initially planar layout into a tubular 3D architecture stabilizes favorable azimuthal magnetic domain patterns. This work creates a solid foundation for further development of CMOS compatible GMI sensorics for magnetoencephalography.
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    Voltage‐Controlled Deblocking of Magnetization Reversal in Thin Films by Tunable Domain Wall Interactions and Pinning Sites
    (Hoboken, NJ : Wiley, 2020) Zehner, Jonas; Soldatov, Ivan; Schneider, Sebastian; Heller, René; Khojasteh, Nasrin B.; Schiemenez, Sandra; Fähler, Sebastian; Nielsch, Kornelius; Schäfer, Rudolf; Leistner, Karin
    High energy efficiency of magnetic devices is crucial for applications such as data storage, computation, and actuation. Redox‐based (magneto‐ionic) voltage control of magnetism is a promising room‐temperature pathway to improve energy efficiency. However, for ferromagnetic metals, the magneto‐ionic effects studied so far require ultrathin films with tunable perpendicular magnetic anisotropy or nanoporous structures for appreciable effects. This paper reports a fully reversible, low voltage‐induced collapse of coercivity and remanence by redox reactions in iron oxide/iron films with uniaxial in‐plane anisotropy. In the initial iron oxide/iron films, Néel wall interactions stabilize a blocked state with high coercivity. During the voltage‐triggered reduction of the iron oxide layer, in situ Kerr microscopy reveals inverse changes of coercivity and anisotropy, and a coarsening of the magnetic microstructure. These results confirm a magneto‐ionic deblocking mechanism, which relies on changes of the Néel wall interactions, and of the microstructural domain‐wall‐pinning sites. With this approach, voltage‐controlled 180° magnetization switching with high energy‐efficiency is achieved. It opens up possibilities for developing magnetic devices programmable by ultralow power and for the reversible tuning of defect‐controlled materials in general.
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    Virtual Testing of Geometrically Imperfect Additively Manufactured Lattice Structures
    (Hoboken, NJ : Wiley, 2021) Gebhardt, Ulrike; Kästner, Markus; Hufenbach, Julia Kristin; Kühn, Uta; Berner, Matthias; Holtzhausen, Stefan
    Additively manufactured lattice structures increase the lightweight potential of components for technical applications. When modelling the mechanical behaviour of those lattice structures, imperfections within the structures need to be considered. In this contribution we investigate the effect of process induced pores of varying size and location inside the lattice structure during pressure tests using a 2D minimal model in two configurations. It shows that the location of pores with respect to the configuration of the model has a strong influence on whether the imperfection decreases the mechanical performance.
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    Architecture engineering of carbonaceous anodes for high‐rate potassium‐ion batteries
    (Hoboken, NJ : Wiley, 2021) Wu, Tianlai; Zhang, Weicai; Yang, Jiaying; Lu, Qiongqiong; Peng, Jing; Zheng, Mingtao; Xu, Fei; Liu, Yingliang; Liang, Yeru
    The limited lithium resource in earth's crust has stimulated the pursuit of alternative energy storage technologies to lithium‐ion battery. Potassium‐ion batteries (KIBs) are regarded as a kind of promising candidate for large‐scale energy storage owing to the high abundance and low cost of potassium resources. Nevertheless, further development and wide application of KIBs are still challenged by several obstacles, one of which is their fast capacity deterioration at high rates. A considerable amount of effort has recently been devoted to address this problem by developing advanced carbonaceous anode materials with diverse structures and morphologies. This review presents and highlights how the architecture engineering of carbonaceous anode materials gives rise to high‐rate performances for KIBs, and also the beneficial conceptions are consciously extracted from the recent progress. Particularly, basic insights into the recent engineering strategies, structural innovation, and the related advances of carbonaceous anodes for high‐rate KIBs are under specific concerns. Based on the achievements attained so far, a perspective on the foregoing, and proposed possible directions, and avenues for designing high‐rate anodes, are presented finally.
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    High-performance magnetic sensorics for printable and flexible electronics
    (Hoboken, NJ : Wiley, 2014) Karnaushenko, Daniil; Makarov, Denys; Stöber, Max; Karnaushenko, Dmitriy D.; Baunack, Stefan; Schmidt, Oliver G.
    High‐performance giant magnetoresistive (GMR) sensorics are realized, which are printed at predefined locations on flexible circuitry. Remarkably, the printed magnetosensors remain fully operational over the complete consumer temperature range and reveal a giant magnetoresistance up to 37% and a sensitivity of 0.93 T−1 at 130 mT. With these specifications, printed magnetoelectronics can be controlled using flexible active electronics for the realization of smart packaging and energy‐efficient switches.
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    Stimuli‐responsive microjets with reconfigurable shape
    (Hoboken, NJ : Wiley, 2014) Magdanz, Veronika; Stoychev, Georgi; Ionov, Leonid; Sanchez, Samuel; Schmidt, Oliver.G.
    Flexible thermoresponsive polymeric microjets are formed by the self‐folding of polymeric layers containing a thin Pt film used as catalyst for self‐propulsion in solutions containing hydrogen peroxide. The flexible microjets can reversibly fold and unfold in an accurate manner by applying changes in temperature to the solution in which they are immersed. This effect allows microjets to rapidly start and stop multiple times by controlling the radius of curvature of the microjet. This work opens many possibilities in the field of artificial nanodevices, for fundamental studies on self‐propulsion at the microscale, and also for biorelated applications.
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    Mononuclear clusterfullerene single‐molecule magnet containing strained fused‐pentagons stabilized by a nearly linear metal cyanide cluster
    (Hoboken, NJ : Wiley, 2017) Liu, Fupin; Wang, Song; Gao, Cong-Li; Deng, Qingming; Zhu, Xianjun; Kostanyan, Aram; Westerstrçm, Rasmus; Jin, Fei; Xie, Su‐Yuan; Popov, Alexey A.; Greber, Thomas; Yang, Shangfeng
    Fused‐pentagons results in an increase of local steric strain according to the isolated pentagon rule (IPR), and for all reported non‐IPR clusterfullerenes multiple (two or three) metals are required to stabilize the strained fused‐pentagons, making it difficult to access the single‐atom properties. Herein, we report the syntheses and isolations of novel non‐IPR mononuclear clusterfullerenes MNC@C76 (M=Tb, Y), in which one pair of strained fused‐pentagon is stabilized by a mononuclear cluster. The molecular structures of MNC@C76 (M=Tb, Y) were determined unambiguously by single‐crystal X‐ray diffraction, featuring a non‐IPR C2v(19138)‐C76 cage entrapping a nearly linear MNC cluster, which is remarkably different from the triangular MNC cluster within the reported analogous clusterfullerenes based on IPR‐obeying C82 cages. The TbNC@C76 molecule is found to be a field‐induced single‐molecule magnet (SMM).
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    Magnetic suspension array technology: Controlled synthesis and screening in microfluidic networks
    (Hoboken, NJ : Wiley, 2016) Lin, Gungun; Karnaushenko, Dmitriy D.; Cañón Bermúdez, Gilbert Santiago; Schmidt, Oliver G.; Makarov, Denys
    Information tagging and processing are vital in information‐intensive applications, e.g., telecommunication and high‐throughput drug screening. Magnetic suspension array technology may offer intrinsic advantages to screening applications by enabling high distinguishability, the ease of code generation, and the feasibility of fast code readout, though the practical applicability of magnetic suspension array technology remains hampered by the lack of quality administration of encoded microcarriers. Here, a logic‐controlled microfluidic system enabling controlled synthesis of magnetic suspension arrays in multiphase flow networks is realized. The smart and compact system offers a practical solution for the quality administration and screening of encoded magnetic microcarriers and addresses the universal need of process control for synthesis in microfluidic networks, i.e., on‐demand creation of droplet templates for high information capacity. The demonstration of magnetic suspension array technology enabled by magnetic in‐flow cytometry opens the avenue toward point‐of‐care multiplexed bead‐based assays, clinical diagnostics, and drug discovery.
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    Selective Out‐of‐Plane Optical Coupling between Vertical and Planar Microrings in a 3D Configuration
    (Hoboken, NJ : Wiley, 2020) Valligatla, Sreeramulu; Wang, Jiawei; Madani, Abbas; Naz, Ehsan Saei Ghareh; Hao, Qi; Saggau, Christian Niclaas; Yin, Yin; Ma, Libo; Schmidt, Oliver G.
    3D photonic integrated circuits are expected to play a key role in future optoelectronics with efficient signal transfer between photonic layers. Here, the optical coupling of tubular microcavities, supporting resonances in a vertical plane, with planar microrings, accommodating in‐plane resonances, is explored. In such a 3D coupled composite system with largely mismatched cavity sizes, periodic mode splitting and resonant mode shifts are observed due to mode‐selective interactions. The axial direction of the microtube cavity provides additional design freedom for selective mode coupling, which is achieved by carefully adjusting the axial displacement between the microtube and the microring. The spectral anticrossing behavior is caused by strong coupling in this composite optical system and is excellently reproduced by numerical modeling. Interfacing tubular microcavities with planar microrings is a promising approach toward interlayer light transfer with added optical functionality in 3D photonic systems.
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    Entirely flexible on-site conditioned magnetic sensorics
    (Hoboken, NJ : Wiley, 2016) Münzenrieder, Niko; Karnaushenko, Daniil; Petti, Luisa; Cantarella, Giuseppe; Vogt, Christian; Büthe, Lars; Karnaushenko, Dmitriy D.; Schmidt, Oliver G.; Makarov, Denys; Tröster, Gerhard
    The first entirely flexible integrated magnetic field sensor system is realized consisting of a flexible giant magnetoresistive bridge on‐site conditioned using high‐performance IGZO‐based readout electronics. The system outperforms commercial fully integrated rigid magnetic sensors by at least one order of magnitude, whereas all components stay fully functional when bend to a radius of 5 mm.