Jakob Walowski
YOU?
Author Swipe
View article: Exploring the impact of the inverse Faraday-effect on all-optical helicity-dependent magnetization switching
Exploring the impact of the inverse Faraday-effect on all-optical helicity-dependent magnetization switching Open
All-optical helicity-dependent magnetization switching (AO-HDS) is the quickest data recording technique using only ultrashort laser pulses. FePt grains provide an ideal platform for examining the interaction of effects conducting magnetiz…
View article: Exploring the impact of the inverse Faraday effect on all-optical helicity-dependent magnetization switching
Exploring the impact of the inverse Faraday effect on all-optical helicity-dependent magnetization switching Open
All-optical helicity-dependent magnetization switching (AO-HDS) is the quickest data recording technique using only ultrashort laser pulses. FePt grains provide an ideal platform for examining the interaction of effects conducting magnetiz…
View article: Comparative analysis of THz signal emission from bilayer heterostructures: Wideband and high-frequency THz signal advantage of PtBi-based emitter
Comparative analysis of THz signal emission from bilayer heterostructures: Wideband and high-frequency THz signal advantage of PtBi-based emitter Open
Spintronic THz emitters have attracted much attention due to their desirable properties, such as affordability, ultra-wideband capability, high efficiency, and tunable polarization. In this study, we investigate the characteristics of THz …
View article: Coupling Broadband Terahertz Dipoles to Microscale Resonators
Coupling Broadband Terahertz Dipoles to Microscale Resonators Open
Optically driven spintronic emitters are a unique class of terahertz (THz) sources due to their quasi-two-dimensional geometry and thereby their capability to effectively couple to resonator near fields. Global excitation of the emitters o…
View article: Size and density control of skyrmions with picometer CoFeB thickness variations—observation of zero-field skyrmions and skyrmion merging
Size and density control of skyrmions with picometer CoFeB thickness variations—observation of zero-field skyrmions and skyrmion merging Open
The controlled formation and adjustment of size and density of magnetic skyrmions in Ta/CoFeB/MgO trilayers with low Dzyaloshinskii–Moriya interaction is demonstrated. Close to the out-of-plane to in-plane magnetic spin reorientation trans…
View article: Comparative Analysis of THz Signal Emission from SiO$_2$/CoFeB/Metal Heterostructures: Wideband and High-Frequency THz Signal Advantage of PtBi-based Emitter
Comparative Analysis of THz Signal Emission from SiO$_2$/CoFeB/Metal Heterostructures: Wideband and High-Frequency THz Signal Advantage of PtBi-based Emitter Open
Spintronic THz emitters have attracted much attention due to their desirable properties, such as affordability, ultra-wideband capability, high efficiency, and tunable polarization. In this study, we investigate the characteristics of THz …
View article: Enhancing spin-transfer torque in magnetic tunnel junction devices: Exploring the influence of capping layer materials and thickness on device characteristics
Enhancing spin-transfer torque in magnetic tunnel junction devices: Exploring the influence of capping layer materials and thickness on device characteristics Open
We have developed and optimized two categories of spin-ransfer torque magnetic tunnel junctions (STT-MTJs) that exhibit a high tunnel magnetoresistance ratio, low critical current, high outputpower in the micro-watt range, and auto-oscilla…
View article: Enhancing Spin Transfer Torque in Magnetic Tunnel Junction Devices: Exploring the Influence of Capping Layer Materials and Thickness on Device Characteristics
Enhancing Spin Transfer Torque in Magnetic Tunnel Junction Devices: Exploring the Influence of Capping Layer Materials and Thickness on Device Characteristics Open
We have developed and optimized two categories of spin transfer torque magnetic tunnel junctions (STT-MTJs) that exhibit a high tunnel magnetoresistance (TMR) ratio, low critical current, high outputpower in the micro watt range, and auto-…
View article: Coupling Broadband Terahertz Dipoles to Microscale Resonators
Coupling Broadband Terahertz Dipoles to Microscale Resonators Open
Optically driven spintronic emitters are a unique class of terahertz (THz) sources due to their quasi-two-dimensional geometry and thereby their capability to effectively couple to resonator near fields. Global excitation of the emitters o…
View article: Identification and characterization of various plastics using THz-spectroscopy
Identification and characterization of various plastics using THz-spectroscopy Open
THz spectroscopy has reached imaging capability with a spatial resolution of a few micrometres. This property enables measurements and imaging of biological samples like cells. THz photons have very low photon energies in the millielectron…
View article: Magnetic domain scanning imaging using phase-sensitive THz-pulse detection
Magnetic domain scanning imaging using phase-sensitive THz-pulse detection Open
In our study, we determine the alignment of magnetic domains in a CoFeB layer using THz radiation. We generate THz pulses by fs laser pulses in magnetized CoFeB/Pt heterostructures based on spin currents. An LT-GaAs Auston switch detects t…
View article: Shaping the spin wave spectra of planar 1D magnonic crystals by the geometrical constrains
Shaping the spin wave spectra of planar 1D magnonic crystals by the geometrical constrains Open
We present experimental and numerical studies demonstrating the influence of geometrical parameters on the fundamental spin-wave mode in planar 1D magnonic crystals. The investigated magnonic crystals consist of flat stripes separated by a…
View article: Magnetic domain scanning imaging using phase-sensitive THz-pulse detection
Magnetic domain scanning imaging using phase-sensitive THz-pulse detection Open
In our study, we determine the alignment of magnetic domains in a CoFeB layer using THz radiation. We generate THz-pulses by fs-laser-pulses in magnetized CoFeB/Pt heterostructures, based on spin currents. An LT-GaAs Auston switch detects …
View article: 10.1063/5.0076880.1
10.1063/5.0076880.1 Open
We investigate local THz field generation using spintronic THz emitters to enhance the resolution for micrometer-sized imaging. Far-field imaging with wavelengths above 100 μm limits the resolution to this order of magnitude. By using opti…
View article: Spintronic emitters for super-resolution in THz-spectral imaging
Spintronic emitters for super-resolution in THz-spectral imaging Open
We investigate local THz field generation using spintronic THz emitters to enhance the resolution for micrometer-sized imaging. Far-field imaging with wavelengths above 100 μm limits the resolution to this order of magnitude. By using opti…
View article: Spintronic emitters for super-resolution in THz-spectral imaging
Spintronic emitters for super-resolution in THz-spectral imaging Open
THz-spectroscopy is an attractive imaging tool for scientific research, especially in life science, offering non-destructive interaction with matter due to its low photon energies. However, wavelengths above $100μm$ principally limit its s…
View article: Observation of multi-skyrmion objects created by size and density control in Ta/CoFeB/MgO films
Observation of multi-skyrmion objects created by size and density control in Ta/CoFeB/MgO films Open
Magnetic skyrmions are chiral spin textures with a nontrivial topology that offer a potential for future magnetic memory and storage devices. The controlled formation and adjustment of size and density of magnetic skyrmions in Ta/CoFeB/MgO…
View article: Efficiency of ultrafast optically induced spin transfer in Heusler compounds
Efficiency of ultrafast optically induced spin transfer in Heusler compounds Open
Optically induced spin transfer (OISTR) is a pathway to control magnetization dynamics in complex materials on femto- to attosecond timescales. The direct interaction of the laser field with the material creates transient nonequilibrium st…
View article: Petahertz Spintronics
Petahertz Spintronics Open
The enigmatic coupling between electronic and magnetic phenomena was one of the riddles propelling the development of modern electromagnetism. Today, the fully controlled electric field evolution of ultrashort laser pulses permits the dire…
View article: Observation of spin Nernst photocurrents in topological insulators
Observation of spin Nernst photocurrents in topological insulators Open
The theoretical prediction of topological insulators in 2007 triggered tremendous interest. They are of fundamental interest because of their topological twist in k-space, which comes along with unidirectional, spin-polarized surface-state…
View article: Laser-induced changes of nonlinear electronic transport properties in La<sub>0.75</sub>Ba<sub>0.25</sub>MnO<sub>3</sub>and (La<sub>0.6</sub>Pr<sub>0.4</sub>)<sub>0.67</sub>Ca<sub>0.33</sub>MnO<sub>3</sub>
Laser-induced changes of nonlinear electronic transport properties in La<sub>0.75</sub>Ba<sub>0.25</sub>MnO<sub>3</sub>and (La<sub>0.6</sub>Pr<sub>0.4</sub>)<sub>0.67</sub>Ca<sub>0.33</sub>MnO<sub>3</sub> Open
We report photoinduced effects in nonlinear third harmonic ac electric transport-which is a measure for the density of correlated polarons-in thin films of [Formula: see text] (LBMO) and [Formula: see text] (LPCMO) manganites. Both materia…
View article: Terahertz Spin Currents and Inverse Spin Hall Effect in Thin-Film Heterostructures Containing Complex Magnetic Compounds
Terahertz Spin Currents and Inverse Spin Hall Effect in Thin-Film Heterostructures Containing Complex Magnetic Compounds Open
Terahertz emission spectroscopy (TES) of ultrathin multilayers of magnetic and heavy metals has recently attracted much interest. This method not only provides fundamental insights into photoinduced spin transport and spin–orbit interactio…
View article: Magnetization dynamics in magnonic structures with different geometries: interfaces, notches and waveguides
Magnetization dynamics in magnonic structures with different geometries: interfaces, notches and waveguides Open
The discovery of ultrafast magnetization dynamics 20 years ago has led to a broad variety of experimental techniques to explore phenomena in magnetic materials with high temporal resolution. In the current article we present a study dealin…
View article: Pumping laser excited spins through MgO barriers
Pumping laser excited spins through MgO barriers Open
We present a study of the tunnel magneto-Seebeck (TMS) effect in MgO based magnetic tunnel junctions (MTJs). The electrodes consist of CoFeB with in-plane magnetic anisotropy. The temperature gradients which generate a voltage across the M…
View article: Perspective: Ultrafast magnetism and THz spintronics
Perspective: Ultrafast magnetism and THz spintronics Open
This year the discovery of femtosecond demagnetization by laser pulses is 20 years old. For the first time, this milestone work by Bigot and coworkers gave insight directly into the time scales of microscopic interactions that connect the …
View article: Magnetization switching of FePt nanoparticle recording medium by femtosecond laser pulses
Magnetization switching of FePt nanoparticle recording medium by femtosecond laser pulses Open
Manipulation of magnetization with ultrashort laser pulses is promising for information storage device applications. The dynamic of the magnetization response depends on the energy transfer from the photons to the spins during the initial …