A5056100465- Magnetic properties of thin films
- Characterization and Applications of Magnetic Nanoparticles
- ZnO doping and properties
- Advanced X-ray Imaging Techniques
- Advanced Memory and Neural Computing
- Physics of Superconductivity and Magnetism
- Magnetic Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- Magneto-Optical Properties and Applications
- Theoretical and Computational Physics
- Digital Holography and Microscopy
- Neural Networks and Reservoir Computing
- Fossil Insects in Amber
- Advanced Electron Microscopy Techniques and Applications
- Multiferroics and related materials
- Acoustic Wave Resonator Technologies
- Photonic Crystals and Applications
- Advanced Condensed Matter Physics
- Geomagnetism and Paleomagnetism Studies
- Minerals Flotation and Separation Techniques
- Ion-surface interactions and analysis
- Conducting polymers and applications
- Laser-Plasma Interactions and Diagnostics
- Copper Interconnects and Reliability
- Ferroelectric and Piezoelectric Materials
Chemnitz University of Technology
2014-2022
University of Augsburg
2016-2018
This work demonstrates nanoscale magnetic imaging using bright circularly polarized high-harmonic radiation. We utilize the magneto-optical contrast of worm-like domains in a Co/Pd multilayer structure, obtaining quantitative amplitude and phase maps by lensless imaging. A diffraction-limited spatial resolution 49 nm is achieved with iterative reconstruction enhanced holographic mask. Harnessing exceptional coherence high harmonics, this approach will facilitate quantitative,...
In the growing field of $m\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}g\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}s$, spin waves (magnons) are manipulated as information carriers, particularly for data processing. Thus controlling propagation is paramount interest here. This investigation considers a ferromagnetic bilayer with dipolar coupling potential nonreciprocal magnonic device, in...
In the last decade, two revolutionary concepts in nanomagnetism emerged from research for storage technologies and advanced information processing. The first suggests use of magnetic domain walls ferromagnetic nanowires to permanently store domain-wall racetrack memories. second proposes a hardware realization neuromorphic computing nanomagnets using nonlinear oscillations gigahertz range. Both ideas originate transfer angular momentum conduction electrons localized spins ferromagnets,...
We demonstrate a combined frequency and time domain investigation of injection-locked, constriction-based spin Hall nano-oscillators by Brillouin light scattering (BLS) time-resolved magneto-optical Kerr effect (TR-MOKE). This was achieved applying an alternating current in the GHz regime addition to direct which drives auto-oscillations constriction. In domain, we analyze width locking range, increase intensity reduction linewidth as function applied current. Then show that injection...
We investigated the reversal characteristics of magnetic vortex cores in a two dimensional assembly vortices. The lattice was created by film deposition 30-nm-thick permalloy onto large arrays self-assembled spherical SiO2-particles with diameter 330 nm. core employing write/read tester. This device uses state-of-the-art recording head hard disc drive, which allows imaging as well applying local field pulse to individual successful writing and reading is demonstrated, including switching...
Recent progress in multiferroic materials and spintronic devices has renewed interest metal oxide ferromagnetic ferrimagnetic materials. Here, we report the preparation of thin films nanocrystalline CoFe2O4 (CFO) using an environmentally benign aqueous solution processing route. The evolution structural, optical, magnetic properties as a function postdeposition annealing temperature is reported. For highest (800 °C), remanence, coercivity, resistivity values are comparable with those...
We investigated the magnetization reversal of magnetic vortex structures in a two-dimensional lattice. The were formed by permalloy (Py) film deposition onto large arrays self-assembled spherical SiO2-particles with diameter 330 nm. present dependence nucleation and annihilation field as function Py layer thickness (aspect ratio) temperature. By increasing up to 90 nm or alternatively lowering temperature structure becomes more stable expected. However, increase results onset strong exchange...
The reversal of magnetic bubble helicity through topologically trivial transient states provides an additional degree freedom that promises the development multidimensional memories. A key requirement for this concept is stabilization at ambient conditions on application-compatible substrates. In present work, we demonstrate a routine remanent in high perpendicular anisotropy ${\text{[Co(0.44 nm)/Pt(0.7 nm)]}}_{X},$ $X=48$, 100, and 150 multilayers $\mathrm{Si}/{\mathrm{SiO}}_{2}$ substrates...
Adsorption of α-helical polyaniline self-assembled monolayers onto magnetic substrates containing a thin Co layer determines the magneto-optical response.
Topological objects, such as magnetic vortices in soft-magnetic thin films, have attracted continued attention over the past 20 years for their unique reversal behavior and compelling potential applications. In exchange-coupled ferromagnetic/antiferromagnetic microdisks, high-resolution force microscopy imaging reveals a distorted ferromagnetic vortex structure due to randomly distributed (nonplanar) uncompensated spins at antiferromagnetic/ferromagnetic interface. Further, in-field...
We study layered synthetic antiferromagnets (SAFs) with out-of-plane interface anisotropy, where the layer-wise antiferromagnetic (AF) alignment is induced by interlayer exchange coupling (IEC). By applying low energy He+ focused ion beam irradiation to SAF, a depth-dependent reduction of IEC and anisotropy can be achieved due layer intermixing. As consequence, after irradiation, specific field reversal sequence SAF energetically preferred. When tuning pristine exhibit an inverted reversal,...
We studied the giant magnetoresistance (GMR) effect in [Co/Pt] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> /Co/Cu/Co/[Co/Pt] pseudo-spin-valves with perpendicular magnetic anisotropy (PMA) and analyzed impact of Cu spacer layer thickness as well Co at Cu/Co interface. The magnetotransport measurements were carried out by a four-point probe method current-in-plane geometry room temperature additionally van der Pauw low temperatures....
Interfaces separating ferromagnetic (FM) layers from non-ferromagnetic offer unique properties due to spin–orbit coupling and symmetry breaking, yielding effects such as exchange bias, perpendicular magnetic anisotropy, spin-pumping, spin-transfer torques, conversion between charge spin currents vice versa. These interfacial phenomena play crucial roles in data storage transfer applications, which require the formation of FM nanostructures embedded matrices. Here, we investigate possibility...
In this work, we investigate magneto-acoustic attenuation in thin film multiferroic Lamb wave delay lines. By leveraging interactions, multiferroics have potential to realize passive chip-scale alternatives bulky ferrite devices. For the first time, magnetic field dependence of interactions devices is characterized. Multiferroic heterostructures aluminum nitride and cobalt iron boron are fabricated into lines operating at 7.492 GHz study effect strain nonuniformity on coupling. The waves...
Antiferromagnets (AFMs) with zero net magnetization are proposed as active elements in future spintronic devices. Depending on the critical film thickness and measurement temperature, bimetallic Mn-based alloys transition-metal oxide-based AFMs can host various coexisting ordered, disordered, frustrated AFM phases. Such phases exchange coupled ferromagnetic (FM)/AFM-based heterostructures result unusual magnetic magnetotransport phenomena. Here, we integrate chemically disordered γ-IrMn3...
Ultrafast demagnetization in diverse materials has sparked immense research activities due to its captivating richness and contested underlying mechanisms. Among these, the two most celebrated mechanisms have been spin-flip scattering (SFS) spin transport (ST) of optically excited carriers. In this work, we investigated femtosecond laser-induced ultrafast perpendicular magnetic anisotropy-based synthetic antiferromagnets (p-SAFs) where [Co/Pt]n-1/Co multilayer blocks are separated by Ru or...
The understanding of how spins move at pico- and femtosecond time scales is the goal much modern research in condensed matter physics, with implications for ultrafast more energy-efficient data storage. However, limited comprehension physics behind this phenomenon has hampered possibility realising a commercial technology based on it. Recently, it been suggested that inertial effects should be considered full description spin dynamics these scales, but clear observation such ferromagnets...
This work demonstrates nanoscale magnetic imaging using bright circularly polarized high-harmonic radiation. We utilize the magneto-optical contrast of worm-like domains in a Co/Pd multilayer structure, obtaining quantitative amplitude and phase maps by lensless imaging. A diffraction-limited spatial resolution 49 nm is achieved with iterative reconstruction enhanced holographic mask. Harnessing unique coherence high harmonics, this approach will facilitate quantitative, element-specific...
We demonstrate high-resolution magneto-optical imaging using circularly-polarized high-harmonic radiation. quantitatively map amplitude and phase of the x-ray magnetic circular dichroism at Co M-edge coherent diffractive imaging.
When the size of a magnetic structure becomes comparable to critical length scale, such as exchange length, multidomain spin configuration energetically unfavorable and either single domain or an inhomogeneous magnetization is formed. One example vortex state [1], which considerable technological interest due its unique physical properties, low stray field high integration density. A characterized by in-plane flux closure, can rotate clockwise counterclockwise direction out-of-plane core...
In the last decade, two revolutionary concepts in nano magnetism emerged from research for advanced information processing and storage technologies. The first suggests use of magnetic domain walls (DWs) ferromagnetic nanowires to permanently store DW race-track memories. second proposes a hard- ware realisation neuromorphic computing nanomagnets using nonlinear oscillations GHz range. Both ideas originate transfer angular momentum conduction electrons localised spins ferromagnets, either...
The reversal of magnetic bubble helicity through topologically trivial transient states provides an additional degree freedom that promises the development multidimensional memories. A key requirement for this concept is stabilization at ambient conditions on application-compatible substrates. In present work we demonstrate a routine remanent in high perpendicular anisotropy [(Co(0.44\,nm)/Pt(0.7\,nm)]$_X$, X = 48, 100, 150 multilayers Si/SiO$_2$ substrates by exploring effect external...