Olav Hellwig
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View article: Manifold role of a Ta adhesion layer in pressure-tuned Co/Pt multilayers
Manifold role of a Ta adhesion layer in pressure-tuned Co/Pt multilayers Open
In this study, we systematically compare the impact of a 1.5-nm-thin Ta adhesion layer on the structural and magnetic behavior of Co/Pt multilayers (MLs) sputter-deposited at a low and a high Ar gas pressure. Our focus is a comprehensive s…
View article: Confinement Driven Spin‐Texture Evolution in Directly Written Nanomagnets
Confinement Driven Spin‐Texture Evolution in Directly Written Nanomagnets Open
In low‐dimensional magnetic structures, magnetostatic energy minimization yields a uniform spin‐texture, resembling that of a macroscopic bar magnet, thereby limiting their scope for applications. Here, the formation of non‐collinear spin‐…
View article: Enhancing nanostructure and energy harvesting efficiency in sustainable BCZT piezoelectric materials through calcination temperature optimization
Enhancing nanostructure and energy harvesting efficiency in sustainable BCZT piezoelectric materials through calcination temperature optimization Open
International audience
View article: Reversible Magneto-Ionic Control of Exchange Bias in Coupled Spin-Valve-Like Heterostructures
Reversible Magneto-Ionic Control of Exchange Bias in Coupled Spin-Valve-Like Heterostructures Open
Voltage control of exchange bias (EB) is an important technological goal for low-power spintronic sensor and memory devices. The magneto-ionic (MI) approach for voltage-controlled EB is a promising strategy to achieve this goal, utilizing …
View article: Magnetic, Electronic Structure and Micromagnetic Properties of Ferrimagnetic DyCo3 as a Platform for Ferrimagnetic Skyrmions
Magnetic, Electronic Structure and Micromagnetic Properties of Ferrimagnetic DyCo3 as a Platform for Ferrimagnetic Skyrmions Open
We demonstrate tunable ferrimagnetic properties in both bulk and thin film ferrimagnetic DyCo3 compatible with the hosting of topological magnetic chiral textures, namely skyrmions suitable for integration into spintronic applications with…
View article: Interplay of magnetocrystalline and magnetoelastic anisotropy in epitaxial <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Co</mml:mi><mml:mo>(</mml:mo><mml:mn>10</mml:mn><mml:mover accent="true"><mml:mn>1</mml:mn><mml:mo>¯</mml:mo></mml:mover><mml:mn>0</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:math> films
Interplay of magnetocrystalline and magnetoelastic anisotropy in epitaxial films Open
With the goal of creating an in-plane (IP) uniaxial anisotropy system, we deposited a thickness series of epitaxial Co(101¯0) films grown on Si(110) substrates with Ag(110) and Cr(211) buffer layers by magnetron sputtering. However, quanti…
View article: 2025 roadmap on 3D nanomagnetism
2025 roadmap on 3D nanomagnetism Open
The transition from planar to three-dimensional (3D) magnetic nanostructures represents a significant advancement in both fundamental research and practical applications, offering vast potential for next-generation technologies like ultrah…
View article: Monolithic Integration of Printable PVDF‐TrFE Piezoelectric Multifunctional Devices: From Sensing to Actuation
Monolithic Integration of Printable PVDF‐TrFE Piezoelectric Multifunctional Devices: From Sensing to Actuation Open
This study demonstrates the development of multifunctional printable piezoelectric actuators using PVDF‐TrFE and PEDOT:PSS, capable of operating at low voltages and supporting a wide range of applications. By leveraging the high piezoelect…
View article: Magnetic Nanoparticle‐Mediated Multimodal Cancer Therapy: Hyperthermia, Controlled Drug Release, and Antibody‐Based Precision
Magnetic Nanoparticle‐Mediated Multimodal Cancer Therapy: Hyperthermia, Controlled Drug Release, and Antibody‐Based Precision Open
Research in cancer therapies is rapidly advancing and demands the exploration of innovative approaches to further improve the efficacy of treatment. Here a multimodal approach for cancer therapy is reported which combines bioactive targeti…
View article: Antiferromagnetic domain wall memory with neuromorphic functionality
Antiferromagnetic domain wall memory with neuromorphic functionality Open
Antiferromagnetic materials have unique properties due to their alternating spin arrangements. Their compensated magnetic order, robust against external magnetic fields, prevents long-distance crosstalk from stray fields. Furthermore, anti…
View article: Magneto‐Ionic Control of Coercivity and Domain‐Wall Velocity in Co/Pd Multilayers by Electrochemical Hydrogen Loading
Magneto‐Ionic Control of Coercivity and Domain‐Wall Velocity in Co/Pd Multilayers by Electrochemical Hydrogen Loading Open
Magneto‐ionics, as the electrochemical reconfiguration of magnetic materials at low gating voltages, is a highly energy‐efficient alternative to control magnetism. For the fastest magneto‐ionic concept based on hydrogen, fundamental mechan…
View article: Multilayer Metamaterials with Ferromagnetic Domains Separated by Antiferromagnetic Domain Walls
Multilayer Metamaterials with Ferromagnetic Domains Separated by Antiferromagnetic Domain Walls Open
Magnetic nano‐objects possess great potential for more efficient data processing, storage, and neuromorphic‐type applications. Using high perpendicular magnetic anisotropy synthetic antiferromagnets in the form of multilayer‐based metamate…
View article: Crystallization dynamics of amorphous yttrium iron garnet thin films
Crystallization dynamics of amorphous yttrium iron garnet thin films Open
Yttrium iron garnet (YIG) is a prototypical material in spintronics due to its exceptional magnetic properties. To exploit these properties, high quality thin films need to be manufactured. Deposition techniques like sputter deposition or …
View article: The mechanism of the molecular CISS effect in chiral nano-junctions
The mechanism of the molecular CISS effect in chiral nano-junctions Open
GMR (a) and TMR (b) device structures realized by using helical molecules adsorbed on the substrate and STM-tip, respectively.
View article: Addendum to: Determining the preferred directions of magnetisation in cubic crystals using symmetric polynomial inequalities
Addendum to: Determining the preferred directions of magnetisation in cubic crystals using symmetric polynomial inequalities Open
In Section 5, where the eighth order case is briefly treated, besides the mentioned potential easy axis directions , , , also is possible according to the Timofte half-degree-principle [1].Furthermore, we would like to mention that a comp…
View article: Correction: The mechanism of the molecular CISS effect in chiral nano-junctions
Correction: The mechanism of the molecular CISS effect in chiral nano-junctions Open
Correction for ‘The mechanism of the molecular CISS effect in chiral nano-junctions’ by Thi Ngoc Ha Nguyen et al. , Chem. Sci. , 2024, 15 , 14905–14912, https://doi.org/10.1039/D4SC04435E
View article: Crystallization Dynamics of Amorphous Yttrium Iron Garnet Thin Films
Crystallization Dynamics of Amorphous Yttrium Iron Garnet Thin Films Open
Yttrium iron garnet (YIG) is a prototypical material in spintronics due to its exceptional magnetic properties. To exploit these properties high quality thin films need to be manufactured. Deposition techniques like sputter deposition or p…
View article: Control of Four-Magnon Scattering by Pure Spin Current in a Magnonic Waveguide
Control of Four-Magnon Scattering by Pure Spin Current in a Magnonic Waveguide Open
Spintronic devices have attracted strong interest in neuromorphic computing, because of their inherent nonlinear behavior and synchronization capabilities. To build magnon-based networks between spintronic oscillators acting as neurons, co…
View article: Multilayer metamaterials with mixed ferromagnetic domain core and antiferromagnetic domain wall structure
Multilayer metamaterials with mixed ferromagnetic domain core and antiferromagnetic domain wall structure Open
Magnetic nano-objects possess great potential for more efficient data processing, storage and neuromorphic type of applications. Using high perpendicular magnetic anisotropy synthetic antiferromagnets in the form of multilayer-based metama…
View article: Control of 4-magnon-scattering in a magnonic waveguide by pure spin current
Control of 4-magnon-scattering in a magnonic waveguide by pure spin current Open
We use a pure spin current originating from the spin Hall effect to generate a spin-orbit torque (SOT) strongly reducing the effective damping in an adjacent ferromagnet. Due to additional microwave excitation, large spin-wave amplitudes a…
View article: Coupling of terahertz light with nanometre-wavelength magnon modes via spin–orbit torque
Coupling of terahertz light with nanometre-wavelength magnon modes via spin–orbit torque Open
Spin-based technologies can operate at terahertz frequencies but require manipulation techniques that work at ultrafast timescales to become practical. For instance, devices based on spin waves, also known as magnons, require efficient gen…
View article: Determining the preferred directions of magnetisation in cubic crystals using symmetric polynomial inequalities
Determining the preferred directions of magnetisation in cubic crystals using symmetric polynomial inequalities Open
For a magnetic material, the easy and hard magnetic axes describe the directions of favourable respectively unfavourable alignment of the magnetisation. In this article, we describe how to determine these axes for cubic magnetic crystals. …
View article: Tailoring Exchange‐Dominated Synthetic Layered Antiferromagnets: From Collective Magnetic Reversal to Exchange Bias
Tailoring Exchange‐Dominated Synthetic Layered Antiferromagnets: From Collective Magnetic Reversal to Exchange Bias Open
Not only since the progressive reduction of structure sizes in modern micro‐ and nanotechnology, surface and interface effects have played an ever‐increasing role and nowadays often dominate the behavior of entire systems. Therefore, under…
View article: Spin Dynamics in Patterned Magnetic Multilayers with Perpendicular Magnetic Anisotropy
Spin Dynamics in Patterned Magnetic Multilayers with Perpendicular Magnetic Anisotropy Open
The magnetization dynamics in nanostructures has been extensively studied in the last decades, and nanomagnetism has evolved significantly over that time, discovering new effects, developing numerous applications, and identifying promising…
View article: Role of vibrational properties and electron–phonon coupling on thermal transport across metal-dielectric interfaces with ultrathin metallic interlayers
Role of vibrational properties and electron–phonon coupling on thermal transport across metal-dielectric interfaces with ultrathin metallic interlayers Open
We systematically analyze the influence of 5 nm thick metal interlayers inserted at the interface of several sets of different metal-dielectric systems to determine the parameters that most influence interface transport. Our results show t…
View article: Effects of the rf current and bias field direction on the transition from linear to non-linear gyrotropic dynamics in magnetic vortex structures
Effects of the rf current and bias field direction on the transition from linear to non-linear gyrotropic dynamics in magnetic vortex structures Open
We present a frequency-domain study of the dynamic behavior of a magnetic vortex core within a single Permalloy disk by means of electrical detection and micromagnetic simulations. When exciting the vortex core dynamics in a non-linear reg…