Michaela Lammel
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View article: Auto-oscillations and directional magnon emission induced by spin current injection into large magnetic volumes
Auto-oscillations and directional magnon emission induced by spin current injection into large magnetic volumes Open
The ability to manipulate magnons using electronic currents holds transformative potential for high-frequency signal processing architectures based on insulating magnetic materials. A critical challenge, however, lies in achieving efficien…
View article: Low-temperature-compatible iron garnet films grown by liquid phase epitaxy
Low-temperature-compatible iron garnet films grown by liquid phase epitaxy Open
Single-crystalline yttrium iron garnet (YIG) thin films (< 100 nm) form the backbone of magnonics, owing to the record-low losses affecting their magnetization dynamics. However, thin epitaxial YIG has mostly been investigated under ambien…
View article: Magnetic aftereffect and Barkhausen effect in thin films of the altermagnetic candidate Mn5Si3
Magnetic aftereffect and Barkhausen effect in thin films of the altermagnetic candidate Mn5Si3 Open
Altermagnetism as a third distinct type of collinear magnetic ordering lately attracts vivid attention. We here study the Hall effect response of micron-scale Hall bars patterned into Mn5Si3 thin films, an altermagnet candidate material. R…
View article: Competing ordinary and Hanle magnetoresistance in Pt and Ti thin films
Competing ordinary and Hanle magnetoresistance in Pt and Ti thin films Open
One of the key elements in spintronics research is the spin Hall effect, allowing to generate spin currents from charge currents. A large spin Hall effect is observed in materials with strong spin-orbit coupling, e.g., Pt. Recent research …
View article: Implementation of field-differential phase-resolved microwave magnetic spectroscopy
Implementation of field-differential phase-resolved microwave magnetic spectroscopy Open
Microwave spectroscopies are central to the investigation of magnetic systems by enabling the identification of dynamical resonance modes and by providing quantitative information on key magnetic parameters. Experiments on magnetization dy…
View article: Spin Hall magnetoresistance at the altermagnetic insulator/Pt interface
Spin Hall magnetoresistance at the altermagnetic insulator/Pt interface Open
The resistance of a heavy metal can be modulated by an adjacent magnetic material through the combined effects of the spin Hall effect, inverse spin Hall effect, and dissipation of the spin accumulation at the interface. This phenomenon is…
View article: Inductive noise spectroscopy of thermally excited magnons
Inductive noise spectroscopy of thermally excited magnons Open
State tomography allows to characterize quantum states, and was recently applied to reveal the dynamic magnetization state of a parametrically driven magnet. The identification of non-classical states, such as squeezed states, relies on a …
View article: Competing Ordinary and Hanle Magnetoresistance in Pt and Ti Thin Films
Competing Ordinary and Hanle Magnetoresistance in Pt and Ti Thin Films Open
One of the key elements in spintronics research is the spin Hall effect, allowing to generate spin currents from charge currents. A large spin Hall effect is observed in materials with strong spin orbit coupling, e.g., Pt. Recent research …
View article: Lattice-tunable substituted iron garnets for low-temperature magnonics
Lattice-tunable substituted iron garnets for low-temperature magnonics Open
The synthesis of nm-thick epitaxial films of iron garnets by physical vapor deposition has opened up exciting opportunities for the on-chip generation and processing of microwave signals encoded in magnons. However, iron garnet thin films …
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: Single-crystalline YIG flakes with uniaxial in-plane anisotropy and diverse crystallographic orientations
Single-crystalline YIG flakes with uniaxial in-plane anisotropy and diverse crystallographic orientations Open
We study sub-micron Y3Fe5O12 (YIG) flakes that we produce via mechanical cleaving and exfoliation of YIG single crystals. By characterizing their structural and magnetic properties, we find that these YIG flakes have surfaces oriented alon…
Electrical detectability of magnon-mediated spin current shot noise Open
The spin of so-called squeezed magnons has been shown to deviate from the common value \ensuremath{\Elzxh}, with corresponding changes in the spin-current shot noise. The authors calculate here the magnitude of the concomitant voltage nois…
Lateral Solid Phase Epitaxy of Yttrium Iron Garnet Open
Solid phase epitaxy is a crystallization technique used to produce high quality thin films. Lateral solid phase epitaxy furthermore enables the realization of non-planar structures, which are interesting, e.g., in the field of spintronics.…
Aluminium substituted yttrium iron garnet thin films with reduced Curie temperature Open
Magnetic garnets such as yttrium iron garnet (${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$, YIG) are widely used in spintronic and magnonic devices. Their magnetic and magneto-optical properties can be modified over a wide range by…
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…
Electrical detectability of magnon-mediated spin current shot noise Open
A magnonic spin current crossing a ferromagnet-metal interface is accompanied by spin current shot noise arising from the discrete quanta of spin carried by magnons. In thin films, e.g., the spin of so-called squeezed magnons have been sho…
Aluminium substituted yttrium iron garnet thin films with reduced Curie temperature Open
Magnetic garnets such as yttrium iron garnet (Y$_3$Fe$_5$O$_{12}$, YIG) are widely used in spintronic and magnonic devices. Their magnetic and magneto-optical properties can be modified over a wide range by tailoring their chemical composi…
View article: Crystal Structure Analysis and Magneto‐Transport Investigation of Co<sub>1−<i>x</i></sub>Fe<sub><i>x</i></sub>Si (with <i>x</i> <b>=</b> 0% to <i>x</i> <b>=</b> 20%)
Crystal Structure Analysis and Magneto‐Transport Investigation of Co<sub>1−<i>x</i></sub>Fe<sub><i>x</i></sub>Si (with <i>x</i> <b>=</b> 0% to <i>x</i> <b>=</b> 20%) Open
Cobalt monosilicide, CoSi, belongs to the new class of materials, featuring Weyl nodes in the bulk band structure, located very close to the Fermi energy. By shifting the chemical potential into these Weyl nodes using Fe‐doping, quantum ef…
Control of Nonlocal Magnon Spin Transport via Magnon Drift Currents Open
Spin transport via magnon diffusion in magnetic insulators is important for a broad range of spin-based phenomena and devices. However, the absence of the magnon equivalent of an electric force is a bottleneck. In this Letter, we demonstra…
Atomic Layer Deposition of Yttrium Iron Garnet Thin Films for 3D Magnetic Structures Open
A wide variety of new phenomena such as novel magnetization configurations have been predicted to occur in three dimensional magnetic nanostructures. However, the fabrication of such structures is often challenging due to the specific shap…
Macroscopic time reversal symmetry breaking by staggered spin-momentum interaction Open
Time-reversal (T) symmetry breaking is a fundamental physics concept underpinning a broad science and technology area, including topological magnets, axion physics, dissipationless Hall currents, or spintronic memories. A best known conven…
Anisotropic magneto-thermal transport in Co$_2$MnGa thin films Open
Ferromagnetic Co$_2$MnGa has recently attracted significant attention due to effects related to non-trivial topology of its band structure, however a systematic study of canonical magneto-galvanic transport effects is missing. Focusing on …
View article: Electrochemical Deposition: Thermoelectric Characterization Platform for Electrochemically Deposited Materials (Adv. Electron. Mater. 4/2020)
Electrochemical Deposition: Thermoelectric Characterization Platform for Electrochemically Deposited Materials (Adv. Electron. Mater. 4/2020) Open
Full thermoelectric characterization of electrochemically deposited films is investigated by Heiko Reith and co-workers in article 1901288, using an in-plan zT characterization platform as shown on the back-cover image. The overlay of the …
Thermoelectric Characterization Platform for Electrochemically Deposited Materials Open
Successful optimization of the thermoelectric (TE) performance of materials, described by the figure of merit zT , is a key enabler for its application in energy harvesting or Peltier cooling devices. While the zT value of bulk materials i…
Topological Electronics: Signatures of a Charge Density Wave Phase and the Chiral Anomaly in the Fermionic Material Cobalt Monosilicide CoSi (Adv. Electron. Mater. 2/2020) Open
The framework model of an interplay between charge density waves and topological transport features is investigated in terms of electrical transport by Gabi Schierning and co-workers in article number 1900857. Single-crystalline ribbons of…
Signatures of a Charge Density Wave Phase and the Chiral Anomaly in the Fermionic Material Cobalt Monosilicide CoSi Open
Materials with topological electronic states have emerged as one of the most exciting discoveries of condensed quantum matter, hosting quasiparticles with extremely low effective mass and high mobility. Weyl materials contain such topologi…
View article: All Electrical Access to Topological Transport Features in Mn<sub>1.8</sub>PtSn Films
All Electrical Access to Topological Transport Features in Mn<sub>1.8</sub>PtSn Films Open
The presence of nontrivial magnetic topology can give rise to nonvanishing scalar spin chirality and consequently a topological Hall or Nernst effect. In turn, topological transport signals can serve as indicators for topological spin stru…
Spin-hall-active platinum thin films grown via atomic layer deposition Open
We study the magnetoresistance of yttrium iron garnet/Pt heterostructures in which the Pt layer was grown via atomic layer deposition (ALD). Magnetotransport experiments in three orthogonal rotation planes reveal the hallmark features of s…