Publications (56)
Non-reciprocal spin excitations across the skyrmion-paramagnetic phase transition in MnSi
Tobias Weber, Karin Schmalzl, Johannes Waizner +3
The magnetic excitations of the skyrmion lattice in MnSi comprise a multitude of individual modes, which are non-reciprocal and thereby propagate unidirectionally. We report inelas…
History dependence of the magnetic properties of single-crystal FeCoSi
Andreas Bauer, Markus Garst, Christian Pfleiderer
We report the magnetization, ac susceptibility, and specific heat of optically float-zoned single crystals of FeCoSi, . We determine the magnet…
Compact susceptometer for studies under transverse field geometries at very low temperatures
Felix Rucker, Christian Pfleiderer
We present the design of a compact AC susceptometer for studies under arbitrarily oriented static magnetic fields, in particular magnetic fields oriented transverse to the AC excit…
Generic aspects of skyrmion lattices in chiral magnets
Andreas Bauer, Christian Pfleiderer
Magnetic skyrmions are topologically non-trivial spin whirls that may not be transformed continuously into topologically trivial states such as ferromagnetic spin alignment. In rec…
Network of topological nodal planes, multifold degeneracies, and Weyl points in CoSi
Nico Huber, Kirill Alpin, Grace L. Causer +7
We report the identification of symmetry-enforced nodal planes (NPs) in CoSi providing the missing topological charges in an entire network of band-crossings comprising in addition…
Low-temperature structural investigations of the frustrated quantum antiferromagnets Cs2CuCl(4-x)Br(x)
Natalija van Well, Kateryna Foyevtsova, Saskia Gottlieb-Schoenmeyer +9
Powder X-ray diffraction (PXRD) and single-crystal neutron scattering were used to study in detail the structural properties of the Cs2CuCl(4-x)Br(x) series, good realizations of l…
Optical creation and annihilation of skyrmion patches in a bulk chiral magnet
Jantje Kalin, Sibylle Sievers, Daniel Kalin +6
A key challenge for the realization of future skyrmion devices comprises the controlled creation, annihilation and detection of these topologically non-trivial magnetic spin textur…
Optically excited spin dynamics of thermally metastable skyrmions in FeCoSi
Jantje Kalin, Sibylle Sievers, Heiko Füser +5
We investigate the microwave spin excitations of the cubic chiral magnet FeCoSi as driven by the thermal modulation of magnetic interactions via laser heating and…
Optimization strategies and artefacts of time-involved small angle neutron scattering experiments
Denis Mettus, Alfonso Chacon, Andreas Bauer +2
Kinetic small-angle neutron scattering provides access to the microscopic properties of mesoscale systems under slow, periodic perturbations. By interlocking the phases of neutron…
Polarized inelastic neutron scattering of non-reciprocal spin waves in MnSi
Tobias Weber, Johannes Waizner, Paul Steffens +4
We report spin-polarized inelastic neutron scattering of the dynamical structure factor of the conical magnetic helix in the cubic chiral magnet MnSi. We find that the spectral wei…
Normal and intrinsic anomalous Hall effect in Nb1-yFe2+y
Sven Friedemann, Manuel Brando, William J Duncan +3
The Hall effect on selected samples of the dilution series Nb1-yFe2+y is studied. Normal and anomalous contributions are observed, with positive normal Hall effect dominating at hi…
Small-angle neutron scattering of long-wavelength magnetic modulations in reduced sample dimensions
Grace L. Causer, Alfonso Chacon, André Heinemann +1
Magnetic small-angle neutron scattering (SANS) is ideally suited to provide direct, reciprocal-space information of long-wavelength magnetic modulations, such as helicoids, soliton…
Fluctuation-induced first-order phase transition in Dzyaloshinskii-Moriya helimagnets
Marc Janoschek, Markus Garst, Andreas Bauer +4
Two centuries of research on phase transitions have repeatedly highlighted the importance of critical fluctuations that abound in the vicinity of a critical point. They are at the…
Real-space observation of the low-temperature Skyrmion lattice in Cu2OSeO3(100) single crystal
Gerald Malsch, Peter Milde, Dmytro Ivaneiko +4
Cu2OSeO3 is a skyrmion host material in which two distinct thermodynamically stable skyrmion phases were identified. We report magnetic force microscopy imaging of the low-temperat…
Tunable Cooperativity in Coupled Spin--Cavity Systems
Lukas Liensberger, Franz X. Haslbeck, Andreas Bauer +5
We experimentally study the tunability of the cooperativity in coupled spin--cavity systems by changing the magnetic state of the spin system via an external control parameter. As…
Resonant elastic X-ray scattering of antiferromagnetic superstructures in EuPtSi
Wolfgang Simeth, Andreas Bauer, Christian Franz +6
We report resonant elastic X-ray scattering (REXS) of long-range magnetic order in EuPtSi, combining different scattering geometries with full linear polarization anal…
Interplay of itinerant magnetism and reentrant spin-glass behavior in FeCr
Georg Benka, Andreas Bauer, Philipp Schmakat +4
When suppressing the itinerant antiferromagnetism in chromium by doping with the isostructual itinerant ferromagnet iron, a dome of spin-glass behavior emerges around a putative qu…
Search for pressure-induced tricriticality in Cr
Alexander Schade, Tim Adams, Alfonso Chacon +2
The antiferromagnetic ordering of chromium has long been known for its peculiar physical properties. One of them is the observation of the weak first-order character of the N'eel t…
Positron spectroscopy of point defects in the skyrmion-lattice compound MnSi
Markus Reiner, Andreas Bauer, Michael Leitner +7
Outstanding crystalline perfection is a key requirement for the formation of new forms of electronic order in a vast number of widely different materials. Whereas excellent sample…
Field dependence of non-reciprocal magnons in chiral MnSi
Tobias Weber, Johannes Waizner, Gregory Tucker +6
Spin waves in chiral magnetic materials are strongly influenced by the Dzyaloshinskii-Moriya interaction resulting in intriguing phenomena like non-reciprocal magnon propagation an…
Non-Reciprocal Zone Boundary Magnon Propagation in CuOSeO
Tobias Weber, Niclas Heinsdorf, Michal Stekiel +3
Inelastic neutron scattering in the chiral magnet CuOSeO reveals strong non-reciprocal effects on magnon propagation at the boundary of the nuclear Brillouin zone. The non-…
MIEZE Neutron Spin-Echo Spectroscopy of Strongly Correlated Electron Systems
Christian Franz, Steffen Säubert, Andreas Wendl +8
Recent progress in neutron spin-echo spectroscopy by means of longitudinal Modulation of IntEnsity with Zero Effort (MIEZE) is reviewed. Key technical characteristics are summarize…
Fermi surface of the chiral topological semimetal CoSi
Nico Huber, Sanu Mishra, Ilya Sheikin +6
We report a study of the Fermi surface of the chiral semimetal CoSi and its relationship to a network of multifold topological crossing points,Weyl points, and topological nodal pl…
Confined dipole and exchange spin waves in a bulk chiral magnet with Dzyaloshinskii-Moriya interaction
Ping Che, Ioannis Stasinopoulos, Andrea Mucchietto +5
The Dzyaloshinskii-Moriya interaction (DMI) has an impact on excited spin waves in the chiral magnet CuOSeO by means of introducing asymmetry on their dispersion relations.…
Fermi surface and magnetic breakdown in PdGa
Nico Huber, Ivan Volkau, Alexander Engelhardt +4
We study the electronic structure of the chiral semimetal PdGa by means of the de Haas-van Alphen and Shubnikov-de Haas effect. We find that the Fermi surface of PdGa comprises mul…
Easy-plane ferromagnetism in single-crystal ErB at low temperatures
Christoph Resch, Georg Benka, Andreas Bauer +1
We report a study of single crystals of the hexagonal rare-earth diboride ErB prepared by means of the self-adjusted flux travelling-solvent floating-zone technique. Measurem…
Magnetoelastic hybrid excitations in CeAuAl
Petr Äermák, Astrid Schneidewind, Benqiong Liu +5
The interactions between elementary excitations such as phonons, plasmons, magnons, or particle-hole pairs, drive emergent functionalities and electronic instabilities such as mult…
Rotating skyrmion lattices by spin torques and field or temperature gradients
Karin Everschor, Markus Garst, Benedikt Binz +4
Chiral magnets like MnSi form lattices of skyrmions, i.e. magnetic whirls, which react sensitively to small electric currents j above a critical current density jc. The interplay o…
Cyclotron mass-selective de Haas-van Alphen measurements using temperature modulation
Michelle Hollricher, Andreas Bauer, Leo Maximov +3
We present a temperature-modulated de Haas-van Alphen measurement technique that allows selective addressing of quantum oscillations with different effective masses usin…
Quantum Tricritical Points in NbFe
Sven Friedemann, Will J Duncan, Max Hirschberger +6
Quantum critical points (QCPs) emerge when a 2nd order phase transition is suppressed to zero temperature. In metals the quantum fluctuations at such a QCP can give rise to new pha…
Compositional Studies of Metals with Complex Order by means of the Optical Floating-Zone Technique
Andreas Bauer, Georg Benka, Andreas Neubauer +13
The availability of large high-quality single crystals is an important prerequisite for many studies in solid-state research. The optical floating-zone technique is an elegant meth…
Optical floating zone growth of high-quality Cu2MnAl single crystals
Andreas Neubauer, Florian Jonietz, Martin Meven +5
We report the growth of large single-crystals of Cu2MnAl, a ferromagnetic Heusler compound suitable for polarizing neutron monochromators, by means of optical floating zone under u…
Non-reciprocal magnons in non-centrosymmetric MnSi
Tobias Weber, Johannes Waizner, Gregory S. Tucker +7
Using two cold-neutron triple-axis spectrometers we have succeeded in fully mapping out the field-dependent evolution of the non-reciprocal magnon dispersion relations in all magne…
Neutron depolarization imaging of the hydrostatic pressure dependence of inhomogeneous ferromagnets
Michael Schulz, Andreas Neubauer, Peter Böni +1
The investigation of fragile and potentially inhomogeneous forms of ferromagnetic order under extreme conditions, such as low temperatures and high pressures, is of central interes…
Ferromagnetic resonance with magnetic phase selectivity by means of resonant elastic x-ray scattering on a chiral magnet
Simon Pöllath, Aisha Aqeel, Andreas Bauer +6
Cubic chiral magnets, such as CuOSeO, exhibit a variety of non-collinear spin textures, including a trigonal lattice of spin whirls, so-called skyrmions. Using magnetic…
Magnetoelastic effects in the metallic frustrated antiferromagnet CrB
Tadataka Watanabe, Mai Watanabe, Sakurako Suganuma +2
Hexagonal chromium diboride CrB is a metallic frustrated antiferromagnet with a Néel temperature 88 K. In CrB, Cr 3 electrons not only give rise to localized…
A Field Guide to non-Onsager Quantum Oscillations in Metals
Valentin Leeb, Nico Huber, Christian Pfleiderer +2
Quantum oscillation (QO) measurements constitute a powerful method to measure the Fermi surface (FS) properties of metals. The observation of QOs is usually taken as strong evidenc…
High-resolution neutron depolarization microscopy of the ferromagnetic transitions in NiAl and HgCrSe under pressure
Pau Jorba, Michael Schulz, Daniel S. Hussey +6
We performed neutron imaging of ferromagnetic transitions in NiAl and HgCrSe crystals. These neutron depolarization measurements revealed bulk magnetic inhomogeneities…
Specific heat of the skyrmion lattice phase and field-induced tricritical point in MnSi
Andreas Bauer, Markus Garst, Christian Pfleiderer
We report high-precision measurements of the temperature and magnetic field dependence of the specific heat, C(T,H), across the magnetic phase diagram of MnSi. Clear anomalies esta…
Emergence of mesoscale quantum phase transitions in a ferromagnet
Andreas Wendl, Heike Eisenlohr, Felix Rucker +4
Mesoscale patterns as observed, e.g., in ferromagnets, ferroelectrics, superconductors, mono-molecular films, or block-copolymers, reflect spatial variations of a pertinent order p…
Ultra-high vacuum compatible induction-heated rod casting furnace
Andreas Bauer, Andreas Neubauer, Wolfgang Münzer +5
We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high va…
Shaking and pushing skyrmions: Formation of a non-equilibrium phase with zero critical current
Felix Rucker, Alla Bezvershenko, Denis Mettus +4
In three-dimensional chiral magnets, skyrmions are line-like objects oriented parallel to the applied magnetic field. The efficient coupling of magnetic skyrmion lattices to spin c…
Quantum Oscillations of the Quasiparticle Lifetime in a Metal
Nico Huber, Valentin Leeb, Andreas Bauer +4
Following nearly a century of research, it remains a puzzle that the low-lying excitations of metals are remarkably well explained by effective single-particle theories of non-inte…
Surface pinning and triggered unwinding of skyrmions in a cubic chiral magnet
Peter Milde, Erik Neuber, Andreas Bauer +2
In the cubic chiral magnet FeCoSi a metastable state comprising of topologically nontrivial spin whirls, so-called skyrmions, may be preserved down to low temperature…
Spin-resolved Fermi surface of the localized ferromagnetic Heusler compound CuMnAl measured with spin-polarized positron annihilation
Josef A. Weber, Andreas Bauer, Peter Böni +7
We determined the bulk electronic structure in the prototypical Heusler compound CuMnAl by measuring the Angular Correlation of Annihilation Radiation (2D-ACAR) using spin-pola…
Low-temperature properties of single-crystal CrB
Andreas Bauer, Alexander Regnat, Christian G. F. Blum +6
We report the low-temperature properties of B-enriched single-crystal CrB as prepared from high-purity Cr and B powder by a solid-state reaction and optical float zoni…
Evolution of the spin dynamics during freezing in the spin-glass FeCr
Steffen Säubert, Christian Franz, Johanna K. Jochum +5
In the iron--chromium system, FeCr, a wide dome of spin-glass behavior emerges when the ferromagnetism of iron is suppressed and the antiferromagnetism of chromium em…
Field-induced reorientation of helimagnetic order in CuOSeO probed by magnetic force microscopy
Peter Milde, Laura Köhler, Erik Neuber +6
CuOSeO is an insulating skyrmion-host material with a magnetoelectric coupling giving rise to an electric polarization with a characteristic dependence on the magnetic fiel…
Turn-key module for neutron scattering with sub-micro-eV resolution
Robert Georgii, Georg Brandl, Nikolas Arend +5
We report the development of a compact turn-key module that boosts the resolution in quasi-elastic neutron scattering by several orders of magnitude down to the low sub-micro-eV ra…
RESPECT: Neutron Resonance Spin-Echo Spectrometer for Extreme Studies
Robert Georgii, Jonas Kindervater, Christian Pfleiderer +1
We propose the design of a Resonance SPin-echo spECtrometer for exTreme studies, RESPECT, that is ideally suited for the exploration of non-dispersive processes such as diffusion,…
Symmetry-enforced topological nodal planes at the Fermi surface of a chiral magnet
Marc A. Wilde, Matthias Dodenhöft, Arthur Niedermayr +5
Following over a decade of intense efforts to enable major progress in spintronics devices and quantum information technology by means of materials in which the electronic structur…
Spectroscopic study of the magnetic ground state of NbFe
Daniela Rauch, Mathias Kraken, F. Jochen Litterst +9
We have investigated single crystals and polycrystals from the series NbFe, by electron spin resonance, muon spin relaxation and Mössbau…
Development of a Modular Optically Detected Magnetic Resonance Setup for Optical Experiments in a Variable Temperature Insert
Anh Tong, Andreas Bauer, Markus Kleinhans +6
We developed an optically detected magnetic resonance (ODMR) setup designed for compatibility with a widely used, commercially available helium bath cryostat equipped with a variab…
Scanning probe microscopy in an ultra-low vibration closed-cycle cryostat
Francesca Paola Quacquarelli, Jorge Puebla, Thomas Scheler +8
We report on state-of-the-art scanning probe microscopy measurements performed in a pulse tube based top-loading closed-cycle cryostat with a base temperature of 4 K and a 9 T magn…
Extending MIEZE spectroscopy towards thermal wavelengths
Johanna K. Jochum, Christian Franz, Thomas Keller +1
We propose a Modulation of intensity with zero effort (MIEZE) set-up for high-resolution neutron spectroscopy at momentum transfers up to 3Ã ,energy transfers up to ~ 20 meV…
The longitudinal neutron resonant spin echo spectrometer RESEDA
Christian Franz, Olaf Soltwedel, Christian Fuchs +6
The instrumental layout and technical realisation of the neutron resonant spin echo (NRSE) spectrometer RESEDA at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany, is pr…