68 citations · 164 across the 12 of their papers we have counts for
12 papers
Tailoring Optical Excitation to Control Magnetic Skyrmion Nucleation
Lisa-Marie Kern, Bastian Pfau, Michael Schneider +12
In ferromagnetic multilayers, a single laser pulse with a fluence above an optical nucleation threshold can create magnetic skyrmions, which are randomly distributed over the area…
Deterministic Generation and Guided Motion of Magnetic Skyrmions by Focused He-Ion Irradiation
L. -M. Kern, B. Pfau, V. Deinhart +17
Magnetic skyrmions are quasiparticles with non-trivial topology, envisioned to play a key role in next-generation data technology while simultaneously attracting fundamental resear…
Stabilization of phase noise in spin torque nano oscillators by a phase locked loop
Steffen Wittrock, Martin Kreißig, Bertrand Lacoste +10
The main limitation in order to exploit spin torque nano-oscillators (STNOs) in various potential applications is their large phase noise. In this work, we demonstrate its efficien…
Non-hermiticity in spintronics: oscillation death in coupled spintronic nano-oscillators through emerging exceptional points
Steffen Wittrock, Salvatore Perna, Romain Lebrun +6
The emergence of exceptional points (EPs) in the parameter space of a non-hermitian (2D) eigenvalue problem is studied in a general sense in mathematical physics, and has in the la…
Flicker and random telegraph noise between gyrotropic and dynamic C-state of a vortex based spin torque nano oscillator
Steffen Wittrock, Philippe Talatchian, Miguel Romera +8
Vortex based spin torque nano oscillators (STVOs) can present more complex dynamics than the spin torque induced gyrotropic (G) motion of the vortex core. The respective dynamic mo…
Spin-torque Dynamics for Noise Reduction in Vortex-based Sensors
Mafalda Jotta Garcia, Julien Moulin, Steffen Wittrock +12
Performance of magnetoresistive sensors is today mainly limited by their 1/f low-frequency noise. Here, we study this noise component in vortex-based TMR sensors. We compare the no…
Beyond the gyrotropic motion: dynamic C-state in vortex spin torque oscillators
Steffen Wittrock, Philippe Talatchian, Miguel Romera Rabasa +9
In the present study, we investigate a dynamical mode beyond the gyrotropic (G) motion of a magnetic vortex core in a confined magnetic disk of a nano-pillar spin torque nano oscil…
Influence of flicker noise and nonlinearity on the frequency spectrum of spin torque nano-oscillators
Steffen Wittrock, Philippe Talatchian, Sumito Tsunegi +12
The correlation of phase fluctuations in any type of oscillator fundamentally defines its spectral shape. However, in nonlinear oscillators, such as spin torque nano oscillators, t…
Spin-current manipulation of photoinduced magnetization dynamics in heavy metal / ferromagnet double layer based nanostructures
Steffen Wittrock, Dennis Meyer, Markus Müller +5
Spin currents offer a way to control static and dynamic magnetic properties, and therefore they are crucial for next-generation MRAM devices or spin-torque oscillators. Manipulatin…
Low offset frequency flicker noise in spin torque vortex oscillators
Steffen Wittrock, Sumito Tsunegi, Kay Yakushiji +9
Low frequency noise close to the carrier remains little explored in spin torque nano oscillators. However, it is crucial to investigate as it limits the oscillator's frequency stab…
Spin-transfer torque switching at ultra low current densities
Johannes Christian Leutenantsmeyer, Vladyslav Zbarsky, Steffen Wittrock +9
The influence of the tantalum buffer layer on the magnetic anisotropy of perpendicular Co-Fe-B/MgO based magnetic tunnel junctions is studied using magneto-optical Kerr-spectroscop…
Spin-transfer torque switching below 20 kA/cm in perpendicular magnetic tunnel junctions
Johannes Christian Leutenantsmeyer, Marvin Walter, Steffen Wittrock +4
We demonstrate the reduction of critical spin-transfer torque (STT) switching currents in Co-Fe-B/MgO based magnetic tunnel junctions (MTJ) with perpendicular magnetization anisotr…